diff --git a/Makefile b/Makefile
index 44086f91..346574f0 100644
--- a/Makefile
+++ b/Makefile
@@ -34,6 +34,10 @@ up:
 	echo "Waiting for mariadb to start up..."
 	docker-compose exec -T mysql timeout 60s sh -c "while ! (mysql -udbuser -pdbpass -h maria --execute 'SELECT 1;' > /dev/null 2>&1); do echo -n '.'; sleep 0.1 ; done; echo 'ok'" || (docker-compose ps; docker-compose logs; exit 1)
 
+	# Solution to problem https://stackoverflow.com/questions/50026939/php-mysqli-connect-authentication-method-unknown-to-the-client-caching-sha2-pa
+	# if updated to PHP 7.4 or more, this command is not needed (TODO)
+	docker-compose exec -T mysql timeout 60s sh -c "while ! (mysql --execute \"ALTER USER 'dbuser'@'%' IDENTIFIED WITH mysql_native_password BY 'dbpass';\" > /dev/null 2>&1); do echo -n '.'; sleep 0.1 ; done; echo 'ok'" || (docker-compose ps; docker-compose logs; exit 1)
+
 cli:
 	docker-compose exec php bash
 
diff --git a/README.md b/README.md
index e75e00f6..f6a916bb 100644
--- a/README.md
+++ b/README.md
@@ -169,6 +169,35 @@ Specify table indexes
            default: '{}' 
 ```
 
+### `x-db-default-expression`
+
+Ability to provide default value by database expression
+
+```yaml
+created_at:
+  readOnly: true
+  type: string
+  format: datetime
+  x-db-type: datetime
+  nullable: false
+  x-db-default-expression: current_timestamp()
+```
+
+Note: If both `default` and `x-db-default-expression` are present then `default` will be considered.
+
+```yaml
+created_at:
+  readOnly: true
+  type: string
+  format: datetime
+  x-db-type: datetime
+  nullable: false
+  x-db-default-expression: current_timestamp() # this will be ignored
+  default: "2011-11-11" # this will be considered
+```
+
+Also see: https://dev.mysql.com/doc/refman/8.0/en/data-type-defaults.html
+
 ### Many-to-Many relation definition
 
 There are two ways for define many-to-many relations:
diff --git a/docker-compose.yml b/docker-compose.yml
index 2582e835..7354f954 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -22,7 +22,7 @@ services:
             - maria
         tty: true
     mysql:
-        image: mysql:5.7
+        image: mysql:8
         ports:
             - '13306:3306'
         volumes:
diff --git a/src/generator/default/migration.php b/src/generator/default/migration.php
index 835e8b76..d6195954 100644
--- a/src/generator/default/migration.php
+++ b/src/generator/default/migration.php
@@ -19,13 +19,13 @@ class <?= $migration->fileClassName ?> extends \yii\db\Migration
 {
     public function <?=$isTransactional? 'safeUp':'up'?>()
     {
-<?= str_replace(["'\$this", ")',"], ['$this', '),'], $migration->upCodeString) ?>
+<?= $migration->upCodeString ?>
 
     }
 
     public function <?=$isTransactional? 'safeDown':'down'?>()
     {
-<?= str_replace(["'\$this", ")',"], ['$this', '),'], $migration->downCodeString) ?>
+<?= $migration->downCodeString ?>
 
     }
 }
diff --git a/src/lib/AttributeResolver.php b/src/lib/AttributeResolver.php
index 578de586..3da776e7 100644
--- a/src/lib/AttributeResolver.php
+++ b/src/lib/AttributeResolver.php
@@ -7,6 +7,7 @@
 
 namespace cebe\yii2openapi\lib;
 
+use cebe\yii2openapi\lib\CustomSpecAttr;
 use cebe\yii2openapi\lib\exceptions\InvalidDefinitionException;
 use cebe\yii2openapi\lib\items\Attribute;
 use cebe\yii2openapi\lib\items\AttributeRelation;
@@ -203,7 +204,8 @@ protected function resolveProperty(PropertySchema $property, bool $isRequired):v
                   ->setDescription($property->getAttr('description', ''))
                   ->setReadOnly($property->isReadonly())
                   ->setDefault($property->guessDefault())
-                  ->setXDbType($property->getAttr('x-db-type'))
+                  ->setXDbType($property->getAttr(CustomSpecAttr::DB_TYPE))
+                  ->setXDbDefaultExpression($property->getAttr(CustomSpecAttr::DB_DEFAULT_EXPRESSION))
                   ->setNullable($property->getProperty()->getSerializableData()->nullable ?? null)
                   ->setIsPrimary($property->isPrimaryKey());
         if ($property->isReference()) {
diff --git a/src/lib/ColumnToCode.php b/src/lib/ColumnToCode.php
index b8154898..87045697 100644
--- a/src/lib/ColumnToCode.php
+++ b/src/lib/ColumnToCode.php
@@ -156,7 +156,12 @@ public function getCode(bool $quoted = false):string
             return '$this->' . $this->fluentParts['type'];
         }
         if ($this->isBuiltinType) {
-            $parts = [$this->fluentParts['type'], $this->fluentParts['nullable'], $this->fluentParts['default'], $this->fluentParts['position']];
+            $parts = [
+                $this->fluentParts['type'],
+                $this->fluentParts['nullable'],
+                $this->fluentParts['default'],
+                $this->fluentParts['position']
+            ];
             array_unshift($parts, '$this');
             return implode('->', array_filter(array_map('trim', $parts), 'trim'));
         }
@@ -443,8 +448,9 @@ private function resolveDefaultValue():void
                     $this->fluentParts['default'] = "defaultValue('" . Json::encode($value->getValue()) . "')";
                     $this->rawParts['default'] = $this->defaultValueArray($value->getValue());
                 } else {
-                    $this->fluentParts['default'] = 'defaultExpression("' . self::escapeQuotes((string)$value) . '")';
-                    $this->rawParts['default'] = self::escapeQuotes((string)$value);
+                    // $value instanceof \yii\db\Expression
+                    $this->fluentParts['default'] = 'defaultExpression("' . (string)$value . '")';
+                    $this->rawParts['default'] = (string)$value;
                 }
                 break;
             case 'array':
@@ -454,18 +460,10 @@ private function resolveDefaultValue():void
                     : $this->defaultValueArray($value);
                 break;
             default:
-                $isExpression = StringHelper::startsWith($value, 'CURRENT')
-                    || StringHelper::startsWith($value, 'current')
-                    || StringHelper::startsWith($value, 'LOCAL')
-                    || substr($value, -1, 1) === ')';
-                if ($isExpression) {
-                    $this->fluentParts['default'] = 'defaultExpression("' . self::escapeQuotes((string)$value) . '")';
-                    $this->rawParts['default'] = $value;
-                } else {
-                    $this->fluentParts['default'] = $expectInteger
-                        ? 'defaultValue(' . $value . ')' : 'defaultValue("' . self::escapeQuotes((string)$value) . '")';
-                    $this->rawParts['default'] = $expectInteger ? $value : self::wrapQuotes($value);
-                }
+                $this->fluentParts['default'] = $expectInteger
+                    ? 'defaultValue(' . $value . ')' : 'defaultValue("' . self::escapeQuotes((string)$value) . '")';
+                $this->rawParts['default'] = $expectInteger ? $value : self::wrapQuotes($value);
+
                 if ((ApiGenerator::isMysql() || ApiGenerator::isMariaDb()) && $this->isEnum()) {
                     $this->rawParts['default'] = self::escapeQuotes($this->rawParts['default']);
                 }
@@ -474,6 +472,11 @@ private function resolveDefaultValue():void
 
     private function isDefaultAllowed():bool
     {
+        // default expression with parenthases is allowed
+        if ($this->column->defaultValue instanceof \yii\db\Expression) {
+            return true;
+        }
+
         $type = strtolower($this->column->dbType);
         switch ($type) {
             case 'tsvector':
diff --git a/src/lib/CustomSpecAttr.php b/src/lib/CustomSpecAttr.php
index f53f6eb4..3c2fe7f1 100644
--- a/src/lib/CustomSpecAttr.php
+++ b/src/lib/CustomSpecAttr.php
@@ -22,4 +22,11 @@ class CustomSpecAttr
     public const FAKER = 'x-faker';
     // Custom db type (MUST CONTAINS ONLY DB TYPE! (json, jsonb, uuid, varchar etc))
     public const DB_TYPE = 'x-db-type';
+    /**
+     * Provide default value by database expression
+     * @example `current_timestamp()`
+     * @see https://dev.mysql.com/doc/refman/8.0/en/data-type-defaults.html
+     * @see https://github.com/cebe/yii2-openapi/blob/master/README.md#x-db-default-expression
+     */
+    public const DB_DEFAULT_EXPRESSION = 'x-db-default-expression';
 }
diff --git a/src/lib/items/Attribute.php b/src/lib/items/Attribute.php
index 0c468f22..8c9b19cb 100644
--- a/src/lib/items/Attribute.php
+++ b/src/lib/items/Attribute.php
@@ -146,6 +146,15 @@ public function setXDbType($xDbType):Attribute
         return $this;
     }
 
+    public function setXDbDefaultExpression($xDbDefaultExpression): Attribute
+    {
+        // first priority is given to `default` and then to `x-db-default-expression`
+        if ($xDbDefaultExpression !== null && $this->defaultValue === null) {
+            $this->defaultValue = new \yii\db\Expression('('.$xDbDefaultExpression.')');
+        }
+        return $this;
+    }
+
     public function setNullable($nullable):Attribute
     {
         $this->nullable = $nullable;
diff --git a/src/lib/migrations/MigrationRecordBuilder.php b/src/lib/migrations/MigrationRecordBuilder.php
index 24989c4f..a46c093f 100644
--- a/src/lib/migrations/MigrationRecordBuilder.php
+++ b/src/lib/migrations/MigrationRecordBuilder.php
@@ -70,7 +70,8 @@ public function createTable(string $tableAlias, array $columns):string
             }
         }
 
-        $codeColumns = str_replace([PHP_EOL, "\\\'"], [PHP_EOL . self::INDENT, "'"], VarDumper::export($codeColumns));
+        $codeColumns = static::makeString($codeColumns);
+
         return sprintf(self::ADD_TABLE, $tableAlias, $codeColumns);
     }
 
@@ -290,4 +291,28 @@ public static function quote(string $columnName): string
         }
         return $columnName;
     }
+
+    /**
+     * Convert code columns array to comlpete syntactically correct PHP code string which will be written to migration file
+     */
+    public static function makeString(array $codeColumns): string
+    {
+        $finalStr = ''.PHP_EOL;
+        foreach ($codeColumns as $key => $column) {
+            if (is_string($key)) {
+                if (substr($column, 0, 5) === '$this') {
+                    $finalStr .= VarDumper::export($key).' => '.$column.','.PHP_EOL;
+                } else {
+                    $finalStr .= VarDumper::export($key).' => '.VarDumper::export($column).','.PHP_EOL;
+                }
+            } else {
+                $finalStr .= VarDumper::export($key).' => '.VarDumper::export($column).','.PHP_EOL;
+            }
+        }
+
+        $codeColumns = str_replace([PHP_EOL, "\\\'"], [PHP_EOL . self::INDENT.'    ', "'"], $finalStr);
+        $codeColumns = trim($codeColumns);
+        $codeColumns = '['.PHP_EOL.self::INDENT.'    '.$codeColumns.PHP_EOL . self::INDENT.']';
+        return $codeColumns;
+    }
 }
diff --git a/tests/fixtures/blog.php b/tests/fixtures/blog.php
index deffbd6d..1d373c71 100644
--- a/tests/fixtures/blog.php
+++ b/tests/fixtures/blog.php
@@ -26,7 +26,7 @@
             'flags' => (new Attribute('flags', ['phpType'=>'int', 'dbType'=>'integer']))->setDefault(0)->setFakerStub
             ('$faker->numberBetween(0, 1000000)'),
             'created_at' => (new Attribute('created_at', ['phpType' => 'string', 'dbType' => 'datetime']))
-                ->setDefault('CURRENT_TIMESTAMP')->setFakerStub('$faker->dateTimeThisYear(\'now\', \'UTC\')->format(DATE_ATOM)'),
+                ->setDefault(new \yii\db\Expression('(CURRENT_TIMESTAMP)'))->setFakerStub('$faker->dateTimeThisYear(\'now\', \'UTC\')->format(DATE_ATOM)'),
         ],
         'relations' => [],
         'indexes' => [
diff --git a/tests/specs/blog.yaml b/tests/specs/blog.yaml
index 1021b843..4da49119 100644
--- a/tests/specs/blog.yaml
+++ b/tests/specs/blog.yaml
@@ -77,7 +77,7 @@ components:
         created_at:
           type: string
           format: date-time
-          default: CURRENT_TIMESTAMP
+          x-db-default-expression: CURRENT_TIMESTAMP
     Users:
       type: array
       items:
diff --git a/tests/specs/blog/migrations/m200000_000001_create_table_users.php b/tests/specs/blog/migrations/m200000_000001_create_table_users.php
index f8cd744a..69e23f8e 100644
--- a/tests/specs/blog/migrations/m200000_000001_create_table_users.php
+++ b/tests/specs/blog/migrations/m200000_000001_create_table_users.php
@@ -14,7 +14,7 @@ public function up()
             'password' => $this->string()->notNull(),
             'role' => $this->string(20)->null()->defaultValue("reader"),
             'flags' => $this->integer()->null()->defaultValue(0),
-            'created_at' => $this->timestamp()->null()->defaultExpression("CURRENT_TIMESTAMP"),
+            'created_at' => $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"),
         ]);
         $this->createIndex('users_username_key', '{{%users}}', 'username', true);
         $this->createIndex('users_email_key', '{{%users}}', 'email', true);
diff --git a/tests/specs/blog/migrations_maria_db/m200000_000001_create_table_users.php b/tests/specs/blog/migrations_maria_db/m200000_000001_create_table_users.php
index f8cd744a..69e23f8e 100644
--- a/tests/specs/blog/migrations_maria_db/m200000_000001_create_table_users.php
+++ b/tests/specs/blog/migrations_maria_db/m200000_000001_create_table_users.php
@@ -14,7 +14,7 @@ public function up()
             'password' => $this->string()->notNull(),
             'role' => $this->string(20)->null()->defaultValue("reader"),
             'flags' => $this->integer()->null()->defaultValue(0),
-            'created_at' => $this->timestamp()->null()->defaultExpression("CURRENT_TIMESTAMP"),
+            'created_at' => $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"),
         ]);
         $this->createIndex('users_username_key', '{{%users}}', 'username', true);
         $this->createIndex('users_email_key', '{{%users}}', 'email', true);
diff --git a/tests/specs/blog/migrations_mysql_db/m200000_000001_create_table_users.php b/tests/specs/blog/migrations_mysql_db/m200000_000001_create_table_users.php
index f8cd744a..69e23f8e 100644
--- a/tests/specs/blog/migrations_mysql_db/m200000_000001_create_table_users.php
+++ b/tests/specs/blog/migrations_mysql_db/m200000_000001_create_table_users.php
@@ -14,7 +14,7 @@ public function up()
             'password' => $this->string()->notNull(),
             'role' => $this->string(20)->null()->defaultValue("reader"),
             'flags' => $this->integer()->null()->defaultValue(0),
-            'created_at' => $this->timestamp()->null()->defaultExpression("CURRENT_TIMESTAMP"),
+            'created_at' => $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"),
         ]);
         $this->createIndex('users_username_key', '{{%users}}', 'username', true);
         $this->createIndex('users_email_key', '{{%users}}', 'email', true);
diff --git a/tests/specs/blog/migrations_pgsql_db/m200000_000001_create_table_users.php b/tests/specs/blog/migrations_pgsql_db/m200000_000001_create_table_users.php
index 23fadf71..00fd8c91 100644
--- a/tests/specs/blog/migrations_pgsql_db/m200000_000001_create_table_users.php
+++ b/tests/specs/blog/migrations_pgsql_db/m200000_000001_create_table_users.php
@@ -14,7 +14,7 @@ public function safeUp()
             'password' => $this->string()->notNull(),
             'role' => $this->string(20)->null()->defaultValue("reader"),
             'flags' => $this->integer()->null()->defaultValue(0),
-            'created_at' => $this->timestamp()->null()->defaultExpression("CURRENT_TIMESTAMP"),
+            'created_at' => $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"),
         ]);
         $this->createIndex('users_username_key', '{{%users}}', 'username', true);
         $this->createIndex('users_email_key', '{{%users}}', 'email', true);
diff --git a/tests/specs/blog_v2/migrations_mysql_db/m200000_000000_change_table_v2_posts.php b/tests/specs/blog_v2/migrations_mysql_db/m200000_000000_change_table_v2_posts.php
index 5c43dabf..be309829 100644
--- a/tests/specs/blog_v2/migrations_mysql_db/m200000_000000_change_table_v2_posts.php
+++ b/tests/specs/blog_v2/migrations_mysql_db/m200000_000000_change_table_v2_posts.php
@@ -19,10 +19,10 @@ public function up()
     public function down()
     {
         $this->createIndex('v2_posts_slug_key', '{{%v2_posts}}', 'slug', true);
-        $this->alterColumn('{{%v2_posts}}', 'created_by_id', $this->integer(11)->null()->defaultValue(null));
+        $this->alterColumn('{{%v2_posts}}', 'created_by_id', $this->integer()->null()->defaultValue(null));
         $this->alterColumn('{{%v2_posts}}', 'active', $this->tinyInteger(1)->notNull()->defaultValue(0));
-        $this->alterColumn('{{%v2_posts}}', 'category_id', $this->integer(11)->notNull());
-        $this->addColumn('{{%v2_posts}}', 'uid', $this->bigInteger(20)->notNull()->first());
+        $this->alterColumn('{{%v2_posts}}', 'category_id', $this->integer()->notNull());
+        $this->addColumn('{{%v2_posts}}', 'uid', $this->bigInteger()->notNull()->first());
         $this->dropColumn('{{%v2_posts}}', 'lang');
         $this->dropColumn('{{%v2_posts}}', 'id');
     }
diff --git a/tests/specs/blog_v2/migrations_mysql_db/m200000_000005_change_table_v2_comments.php b/tests/specs/blog_v2/migrations_mysql_db/m200000_000005_change_table_v2_comments.php
index 8ac64b7b..1b4ac400 100644
--- a/tests/specs/blog_v2/migrations_mysql_db/m200000_000005_change_table_v2_comments.php
+++ b/tests/specs/blog_v2/migrations_mysql_db/m200000_000005_change_table_v2_comments.php
@@ -7,8 +7,8 @@ class m200000_000005_change_table_v2_comments extends \yii\db\Migration
 {
     public function up()
     {
-        $this->dropForeignKey('fk_v2_comments_post_id_v2_posts_uid', '{{%v2_comments}}');
         $this->dropForeignKey('fk_v2_comments_author_id_v2_users_id', '{{%v2_comments}}');
+        $this->dropForeignKey('fk_v2_comments_post_id_v2_posts_uid', '{{%v2_comments}}');
         $this->addColumn('{{%v2_comments}}', 'user_id', $this->bigInteger()->null()->defaultValue(null)->after('post_id'));
         $this->dropColumn('{{%v2_comments}}', 'author_id');
         $this->alterColumn('{{%v2_comments}}', 'message', $this->text()->notNull());
@@ -22,12 +22,12 @@ public function down()
     {
         $this->dropForeignKey('fk_v2_comments_user_id_v2_users_id', '{{%v2_comments}}');
         $this->dropForeignKey('fk_v2_comments_post_id_v2_posts_id', '{{%v2_comments}}');
-        $this->alterColumn('{{%v2_comments}}', 'created_at', $this->integer(11)->notNull());
+        $this->alterColumn('{{%v2_comments}}', 'created_at', $this->integer()->notNull());
         $this->alterColumn('{{%v2_comments}}', 'meta_data', 'json NOT NULL');
         $this->alterColumn('{{%v2_comments}}', 'message', 'json NOT NULL');
-        $this->addColumn('{{%v2_comments}}', 'author_id', $this->integer(11)->notNull());
+        $this->addColumn('{{%v2_comments}}', 'author_id', $this->integer()->notNull());
         $this->dropColumn('{{%v2_comments}}', 'user_id');
-        $this->addForeignKey('fk_v2_comments_author_id_v2_users_id', '{{%v2_comments}}', 'id', 'v2_users', 'author_id');
         $this->addForeignKey('fk_v2_comments_post_id_v2_posts_uid', '{{%v2_comments}}', 'uid', 'v2_posts', 'post_id');
+        $this->addForeignKey('fk_v2_comments_author_id_v2_users_id', '{{%v2_comments}}', 'id', 'v2_users', 'author_id');
     }
 }
diff --git a/tests/specs/issue_fix/create_table_in_down_code/create_table_in_down_code.php b/tests/specs/issue_fix/create_table_in_down_code/create_table_in_down_code.php
new file mode 100644
index 00000000..40f6e1db
--- /dev/null
+++ b/tests/specs/issue_fix/create_table_in_down_code/create_table_in_down_code.php
@@ -0,0 +1,13 @@
+<?php
+
+return [
+    'openApiPath' => '@specs/issue_fix/create_table_in_down_code/create_table_in_down_code.yaml',
+    'generateUrls' => false,
+    'generateModels' => false,
+    'excludeModels' => [
+        'Error',
+    ],
+    'generateControllers' => false,
+    'generateMigrations' => true,
+    'generateModelFaker' => false,
+];
diff --git a/tests/specs/issue_fix/create_table_in_down_code/create_table_in_down_code.yaml b/tests/specs/issue_fix/create_table_in_down_code/create_table_in_down_code.yaml
new file mode 100644
index 00000000..849ec35d
--- /dev/null
+++ b/tests/specs/issue_fix/create_table_in_down_code/create_table_in_down_code.yaml
@@ -0,0 +1,24 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Create table in down code
+paths:
+  /:
+    get:
+      summary: List
+      operationId: list
+      responses:
+        '200':
+          description: The information
+
+components:
+  schemas:
+    Fruit:
+      type: object
+      description: Create table in down code
+      properties:
+        id:
+          type: integer
+        colourName:
+          type: string
+          maxLength: 255
diff --git a/tests/specs/x_db_default_expression/maria/edit/app/migrations_maria_db/m200000_000000_change_table_fruits.php b/tests/specs/x_db_default_expression/maria/edit/app/migrations_maria_db/m200000_000000_change_table_fruits.php
new file mode 100644
index 00000000..bafd270b
--- /dev/null
+++ b/tests/specs/x_db_default_expression/maria/edit/app/migrations_maria_db/m200000_000000_change_table_fruits.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_change_table_fruits extends \yii\db\Migration
+{
+    public function up()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultValue("2011-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->null()->defaultValue("2000-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'd3', $this->text()->null()->defaultValue("text default"));
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+    }
+
+    public function down()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'd3', $this->text()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->notNull()->defaultValue("0000-00-00 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->notNull()->defaultValue("0000-00-00 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->notNull()->defaultExpression("current_timestamp()"));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultValue(null));
+    }
+}
diff --git a/tests/specs/x_db_default_expression/maria/edit_expression/app/migrations_maria_db/m200000_000000_change_table_fruits.php b/tests/specs/x_db_default_expression/maria/edit_expression/app/migrations_maria_db/m200000_000000_change_table_fruits.php
new file mode 100644
index 00000000..de29b6a7
--- /dev/null
+++ b/tests/specs/x_db_default_expression/maria/edit_expression/app/migrations_maria_db/m200000_000000_change_table_fruits.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_change_table_fruits extends \yii\db\Migration
+{
+    public function up()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultValue("2011-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->null()->defaultValue("2000-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'd3', $this->text()->null()->defaultValue("text default"));
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+    }
+
+    public function down()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultValue("2011-11-11"));
+        $this->alterColumn('{{%fruits}}', 'd3', $this->text()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultValue("2011-11-11"));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->notNull()->defaultExpression("current_timestamp()"));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->notNull()->defaultValue("2011-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->notNull()->defaultExpression("current_timestamp()"));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultExpression("current_timestamp()"));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultExpression("current_timestamp()"));
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultValue("2011-11-11 00:00:00"));
+    }
+}
diff --git a/tests/specs/x_db_default_expression/maria/simple/app/migrations_maria_db/m200000_000000_create_table_fruits.php b/tests/specs/x_db_default_expression/maria/simple/app/migrations_maria_db/m200000_000000_create_table_fruits.php
new file mode 100644
index 00000000..3348044e
--- /dev/null
+++ b/tests/specs/x_db_default_expression/maria/simple/app/migrations_maria_db/m200000_000000_create_table_fruits.php
@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_create_table_fruits extends \yii\db\Migration
+{
+    public function up()
+    {
+        $this->createTable('{{%fruits}}', [
+            'ts' => $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"),
+            'ts2' => $this->timestamp()->null()->defaultValue("2011-11-11 00:00:00"),
+            'ts3' => $this->timestamp()->null()->defaultValue("2022-11-11 00:00:00"),
+            0 => 'ts4 timestamp NULL DEFAULT \'2022-11-11 00:00:00\'',
+            1 => 'ts5 timestamp NULL DEFAULT (CURRENT_TIMESTAMP)',
+            2 => 'ts6 timestamp NULL DEFAULT \'2000-11-11 00:00:00\'',
+            3 => 'd date NULL DEFAULT (CURRENT_DATE + INTERVAL 1 YEAR)',
+            4 => 'd2 text NULL DEFAULT (CURRENT_DATE + INTERVAL 1 YEAR)',
+            5 => 'd3 text NULL DEFAULT \'text default\'',
+            'ts7' => $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"),
+        ]);
+    }
+
+    public function down()
+    {
+        $this->dropTable('{{%fruits}}');
+    }
+}
diff --git a/tests/specs/x_db_default_expression/mysql/edit/app/migrations_mysql_db/m200000_000000_change_table_fruits.php b/tests/specs/x_db_default_expression/mysql/edit/app/migrations_mysql_db/m200000_000000_change_table_fruits.php
new file mode 100644
index 00000000..35857636
--- /dev/null
+++ b/tests/specs/x_db_default_expression/mysql/edit/app/migrations_mysql_db/m200000_000000_change_table_fruits.php
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_change_table_fruits extends \yii\db\Migration
+{
+    public function up()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultValue("2011-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->null()->defaultValue("2000-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+    }
+
+    public function down()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null());
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultValue(null));
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultValue(null));
+    }
+}
diff --git a/tests/specs/x_db_default_expression/mysql/edit_expression/app/migrations_mysql_db/m200000_000000_change_table_fruits.php b/tests/specs/x_db_default_expression/mysql/edit_expression/app/migrations_mysql_db/m200000_000000_change_table_fruits.php
new file mode 100644
index 00000000..df83564e
--- /dev/null
+++ b/tests/specs/x_db_default_expression/mysql/edit_expression/app/migrations_mysql_db/m200000_000000_change_table_fruits.php
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_change_table_fruits extends \yii\db\Migration
+{
+    public function up()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultValue("2011-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->null()->defaultValue("2022-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->null()->defaultValue("2000-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"));
+    }
+
+    public function down()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts7', $this->date()->null()->defaultValue("2011-11-11"));
+        $this->alterColumn('{{%fruits}}', 'd2', $this->text()->null());
+        $this->alterColumn('{{%fruits}}', 'd', $this->date()->null()->defaultValue("2011-11-11"));
+        $this->alterColumn('{{%fruits}}', 'ts6', $this->timestamp()->null()->defaultExpression("CURRENT_TIMESTAMP"));
+        $this->alterColumn('{{%fruits}}', 'ts5', $this->timestamp()->null()->defaultValue("2011-11-11 00:00:00"));
+        $this->alterColumn('{{%fruits}}', 'ts4', $this->timestamp()->null()->defaultExpression("CURRENT_TIMESTAMP"));
+        $this->alterColumn('{{%fruits}}', 'ts3', $this->datetime()->null()->defaultExpression("CURRENT_TIMESTAMP"));
+        $this->alterColumn('{{%fruits}}', 'ts2', $this->datetime()->null()->defaultExpression("CURRENT_TIMESTAMP"));
+        $this->alterColumn('{{%fruits}}', 'ts', $this->datetime()->null()->defaultValue("2011-11-11 00:00:00"));
+    }
+}
diff --git a/tests/specs/x_db_default_expression/mysql/simple/app/migrations_mysql_db/m200000_000000_create_table_fruits.php b/tests/specs/x_db_default_expression/mysql/simple/app/migrations_mysql_db/m200000_000000_create_table_fruits.php
new file mode 100644
index 00000000..e60beee3
--- /dev/null
+++ b/tests/specs/x_db_default_expression/mysql/simple/app/migrations_mysql_db/m200000_000000_create_table_fruits.php
@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_create_table_fruits extends \yii\db\Migration
+{
+    public function up()
+    {
+        $this->createTable('{{%fruits}}', [
+            'ts' => $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"),
+            'ts2' => $this->timestamp()->null()->defaultValue("2011-11-11 00:00:00"),
+            'ts3' => $this->timestamp()->null()->defaultValue("2022-11-11 00:00:00"),
+            0 => 'ts4 timestamp NULL DEFAULT \'2022-11-11 00:00:00\'',
+            1 => 'ts5 timestamp NULL DEFAULT (CURRENT_TIMESTAMP)',
+            2 => 'ts6 timestamp NULL DEFAULT \'2000-11-11 00:00:00\'',
+            3 => 'd date NULL DEFAULT (CURRENT_DATE + INTERVAL 1 YEAR)',
+            4 => 'd2 text NULL DEFAULT (CURRENT_DATE + INTERVAL 1 YEAR)',
+            5 => 'd3 text NULL',
+            'ts7' => $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL 1 YEAR)"),
+        ]);
+    }
+
+    public function down()
+    {
+        $this->dropTable('{{%fruits}}');
+    }
+}
diff --git a/tests/specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php b/tests/specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php
new file mode 100644
index 00000000..5fd47d1b
--- /dev/null
+++ b/tests/specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php
@@ -0,0 +1,13 @@
+<?php
+
+return [
+    'openApiPath' => '@specs/x_db_default_expression/mysql/x_db_default_expression_mysql.yaml',
+    'generateUrls' => false,
+    'generateModels' => false,
+    'excludeModels' => [
+        'Error',
+    ],
+    'generateControllers' => false,
+    'generateMigrations' => true,
+    'generateModelFaker' => false,
+];
diff --git a/tests/specs/x_db_default_expression/mysql/x_db_default_expression_mysql.yaml b/tests/specs/x_db_default_expression/mysql/x_db_default_expression_mysql.yaml
new file mode 100644
index 00000000..67ef4f50
--- /dev/null
+++ b/tests/specs/x_db_default_expression/mysql/x_db_default_expression_mysql.yaml
@@ -0,0 +1,71 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: x-db-default-expression test
+paths:
+  /:
+    get:
+      summary: List
+      operationId: list
+      responses:
+        '200':
+          description: The information
+
+components:
+  schemas:
+    Fruit:
+      type: object
+      description: x-db-default-expression test
+      properties:
+        ts:
+          type: string
+          format: datetime
+          # x-db-type: timestamp
+          x-db-default-expression: CURRENT_TIMESTAMP
+        ts2:
+          type: string
+          format: datetime
+          default: '2011-11-11 00:00:00'
+          # x-db-type: timestamp
+          # x-db-default-expression: CURRENT_TIMESTAMP
+        ts3:
+          type: string
+          format: datetime
+          default: '2022-11-11 00:00:00'
+          x-db-default-expression: CURRENT_TIMESTAMP
+        ts4:
+          type: string
+          x-db-type: timestamp
+          default: '2022-11-11 00:00:00'
+        ts5:
+          type: string
+          x-db-type: timestamp
+          x-db-default-expression: CURRENT_TIMESTAMP
+        ts6:
+          type: string
+          x-db-type: timestamp
+          default: '2000-11-11 00:00:00'
+          x-db-default-expression: CURRENT_TIMESTAMP
+        d:
+          type: string
+          x-db-type: date
+          x-db-default-expression: CURRENT_DATE + INTERVAL 1 YEAR
+        d2:
+          type: string
+          x-db-type: text
+          x-db-default-expression: CURRENT_DATE + INTERVAL 1 YEAR
+        d3:
+          type: string
+          x-db-type: text
+          default: text default # default literal constant for 'text' is not allowed in MySQL
+          x-db-default-expression: CURRENT_DATE + INTERVAL 1 YEAR
+        ts7:
+          type: string
+          format: date
+          x-db-default-expression: CURRENT_DATE + INTERVAL 1 YEAR
+
+        # https://github.com/yiisoft/yii2/issues/19747
+        # ts8:
+        #   type: string
+        #   format: date
+        #   x-db-default-expression: CURRENT_DATE + INTERVAL 1 YEAR
diff --git a/tests/specs/x_db_default_expression/pgsql/edit/app/migrations_pgsql_db/m200000_000000_change_table_fruits.php b/tests/specs/x_db_default_expression/pgsql/edit/app/migrations_pgsql_db/m200000_000000_change_table_fruits.php
new file mode 100644
index 00000000..22d85a96
--- /dev/null
+++ b/tests/specs/x_db_default_expression/pgsql/edit/app/migrations_pgsql_db/m200000_000000_change_table_fruits.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_change_table_fruits extends \yii\db\Migration
+{
+    public function safeUp()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', "SET DEFAULT (CURRENT_TIMESTAMP)");
+        $this->alterColumn('{{%fruits}}', 'ts2', "SET DEFAULT '2011-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts3', "SET DEFAULT '2022-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts4', "SET DEFAULT '2022-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts5', "SET DEFAULT (CURRENT_TIMESTAMP)");
+        $this->alterColumn('{{%fruits}}', 'ts6', "SET DEFAULT '2000-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'd', "SET DEFAULT (CURRENT_DATE + INTERVAL '1 YEAR')");
+        $this->alterColumn('{{%fruits}}', 'd2', "SET DEFAULT (CURRENT_DATE + INTERVAL '1 YEAR')");
+        $this->alterColumn('{{%fruits}}', 'd3', "SET DEFAULT 'text default'");
+        $this->alterColumn('{{%fruits}}', 'ts7', "SET DEFAULT (CURRENT_DATE + INTERVAL '1 YEAR')");
+    }
+
+    public function safeDown()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'ts2', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'ts3', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'ts4', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'ts5', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'ts6', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'd', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'd2', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'd3', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'ts7', "DROP DEFAULT");
+    }
+}
diff --git a/tests/specs/x_db_default_expression/pgsql/edit_expression/app/migrations_pgsql_db/m200000_000000_change_table_fruits.php b/tests/specs/x_db_default_expression/pgsql/edit_expression/app/migrations_pgsql_db/m200000_000000_change_table_fruits.php
new file mode 100644
index 00000000..4372308e
--- /dev/null
+++ b/tests/specs/x_db_default_expression/pgsql/edit_expression/app/migrations_pgsql_db/m200000_000000_change_table_fruits.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_change_table_fruits extends \yii\db\Migration
+{
+    public function safeUp()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', "SET DEFAULT (CURRENT_TIMESTAMP)");
+        $this->alterColumn('{{%fruits}}', 'ts2', "SET DEFAULT '2011-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts3', "SET DEFAULT '2022-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts4', "SET DEFAULT '2022-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts5', "SET DEFAULT (CURRENT_TIMESTAMP)");
+        $this->alterColumn('{{%fruits}}', 'ts6', "SET DEFAULT '2000-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'd', "SET DEFAULT (CURRENT_DATE + INTERVAL '1 YEAR')");
+        $this->alterColumn('{{%fruits}}', 'd2', "SET DEFAULT (CURRENT_DATE + INTERVAL '1 YEAR')");
+        $this->alterColumn('{{%fruits}}', 'd3', "SET DEFAULT 'text default'");
+        $this->alterColumn('{{%fruits}}', 'ts7', "SET DEFAULT (CURRENT_DATE + INTERVAL '1 YEAR')");
+    }
+
+    public function safeDown()
+    {
+        $this->alterColumn('{{%fruits}}', 'ts', "SET DEFAULT '2011-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts2', "SET DEFAULT CURRENT_TIMESTAMP");
+        $this->alterColumn('{{%fruits}}', 'ts3', "SET DEFAULT CURRENT_TIMESTAMP");
+        $this->alterColumn('{{%fruits}}', 'ts4', "SET DEFAULT CURRENT_TIMESTAMP");
+        $this->alterColumn('{{%fruits}}', 'ts5', "SET DEFAULT '2011-11-11 00:00:00'");
+        $this->alterColumn('{{%fruits}}', 'ts6', "SET DEFAULT CURRENT_TIMESTAMP");
+        $this->alterColumn('{{%fruits}}', 'd', "SET DEFAULT '2011-11-11'");
+        $this->alterColumn('{{%fruits}}', 'd2', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'd3', "DROP DEFAULT");
+        $this->alterColumn('{{%fruits}}', 'ts7', "SET DEFAULT '2011-11-11'");
+    }
+}
diff --git a/tests/specs/x_db_default_expression/pgsql/simple/app/migrations_pgsql_db/m200000_000000_create_table_fruits.php b/tests/specs/x_db_default_expression/pgsql/simple/app/migrations_pgsql_db/m200000_000000_create_table_fruits.php
new file mode 100644
index 00000000..5b1494cf
--- /dev/null
+++ b/tests/specs/x_db_default_expression/pgsql/simple/app/migrations_pgsql_db/m200000_000000_create_table_fruits.php
@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * Table for Fruit
+ */
+class m200000_000000_create_table_fruits extends \yii\db\Migration
+{
+    public function safeUp()
+    {
+        $this->createTable('{{%fruits}}', [
+            'ts' => $this->timestamp()->null()->defaultExpression("(CURRENT_TIMESTAMP)"),
+            'ts2' => $this->timestamp()->null()->defaultValue("2011-11-11 00:00:00"),
+            'ts3' => $this->timestamp()->null()->defaultValue("2022-11-11 00:00:00"),
+            0 => '"ts4" timestamp NULL DEFAULT \'2022-11-11 00:00:00\'',
+            1 => '"ts5" timestamp NULL DEFAULT (CURRENT_TIMESTAMP)',
+            2 => '"ts6" timestamp NULL DEFAULT \'2000-11-11 00:00:00\'',
+            3 => '"d" date NULL DEFAULT (CURRENT_DATE + INTERVAL \'1 YEAR\')',
+            4 => '"d2" text NULL DEFAULT (CURRENT_DATE + INTERVAL \'1 YEAR\')',
+            5 => '"d3" text NULL DEFAULT \'text default\'',
+            'ts7' => $this->date()->null()->defaultExpression("(CURRENT_DATE + INTERVAL '1 YEAR')"),
+        ]);
+    }
+
+    public function safeDown()
+    {
+        $this->dropTable('{{%fruits}}');
+    }
+}
diff --git a/tests/specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.php b/tests/specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.php
new file mode 100644
index 00000000..b71e5511
--- /dev/null
+++ b/tests/specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.php
@@ -0,0 +1,13 @@
+<?php
+
+return [
+    'openApiPath' => '@specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.yaml',
+    'generateUrls' => false,
+    'generateModels' => false,
+    'excludeModels' => [
+        'Error',
+    ],
+    'generateControllers' => false,
+    'generateMigrations' => true,
+    'generateModelFaker' => false,
+];
diff --git a/tests/specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.yaml b/tests/specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.yaml
new file mode 100644
index 00000000..b0a37326
--- /dev/null
+++ b/tests/specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.yaml
@@ -0,0 +1,71 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: x-db-default-expression test
+paths:
+  /:
+    get:
+      summary: List
+      operationId: list
+      responses:
+        '200':
+          description: The information
+
+components:
+  schemas:
+    Fruit:
+      type: object
+      description: x-db-default-expression test
+      properties:
+        ts:
+          type: string
+          format: datetime
+          # x-db-type: timestamp
+          x-db-default-expression: CURRENT_TIMESTAMP
+        ts2:
+          type: string
+          format: datetime
+          default: '2011-11-11 00:00:00'
+          # x-db-type: timestamp
+          # x-db-default-expression: CURRENT_TIMESTAMP
+        ts3:
+          type: string
+          format: datetime
+          default: '2022-11-11 00:00:00'
+          x-db-default-expression: CURRENT_TIMESTAMP
+        ts4:
+          type: string
+          x-db-type: timestamp
+          default: '2022-11-11 00:00:00'
+        ts5:
+          type: string
+          x-db-type: timestamp
+          x-db-default-expression: CURRENT_TIMESTAMP
+        ts6:
+          type: string
+          x-db-type: timestamp
+          default: '2000-11-11 00:00:00'
+          x-db-default-expression: CURRENT_TIMESTAMP
+        d:
+          type: string
+          x-db-type: date
+          x-db-default-expression: CURRENT_DATE + INTERVAL '1 YEAR'
+        d2:
+          type: string
+          x-db-type: text
+          x-db-default-expression: CURRENT_DATE + INTERVAL '1 YEAR'
+        d3:
+          type: string
+          x-db-type: text
+          default: text default # default literal constant for 'text' is not allowed in MySQL
+          x-db-default-expression: CURRENT_DATE + INTERVAL '1 YEAR'
+        ts7:
+          type: string
+          format: date
+          x-db-default-expression: CURRENT_DATE + INTERVAL '1 YEAR'
+
+        # https://github.com/yiisoft/yii2/issues/19747
+        # ts8:
+        #   type: string
+        #   format: date
+        #   x-db-default-expression: CURRENT_DATE + INTERVAL 1 YEAR
diff --git a/tests/specs/x_db_type/edit_column/mysql/app/migrations_mysql_db/m200000_000001_change_table_editcolumns.php b/tests/specs/x_db_type/edit_column/mysql/app/migrations_mysql_db/m200000_000001_change_table_editcolumns.php
index 88b873ca..29b8129b 100644
--- a/tests/specs/x_db_type/edit_column/mysql/app/migrations_mysql_db/m200000_000001_change_table_editcolumns.php
+++ b/tests/specs/x_db_type/edit_column/mysql/app/migrations_mysql_db/m200000_000001_change_table_editcolumns.php
@@ -21,7 +21,7 @@ public function up()
 
     public function down()
     {
-        $this->alterColumn('{{%editcolumns}}', 'numeric_col', $this->integer(11)->null()->defaultValue(null));
+        $this->alterColumn('{{%editcolumns}}', 'numeric_col', $this->integer()->null()->defaultValue(null));
         $this->alterColumn('{{%editcolumns}}', 'json_col_2', 'json NULL');
         $this->alterColumn('{{%editcolumns}}', 'json_col', 'json NULL');
         $this->alterColumn('{{%editcolumns}}', 'str_col_def', $this->string(255)->null()->defaultValue("hi there"));
diff --git a/tests/unit/IssueFixTest.php b/tests/unit/IssueFixTest.php
index fce08548..c3890bb6 100644
--- a/tests/unit/IssueFixTest.php
+++ b/tests/unit/IssueFixTest.php
@@ -127,4 +127,39 @@ private function createTableForQuoteInAlterColumn()
             'colourName' => 'varchar(255)',
         ])->execute();
     }
+
+    // Stub -> https://github.com/cebe/yii2-openapi/issues/132
+    // public function testCreateTableInDownCode()
+    // {
+    //     $testFile = Yii::getAlias("@specs/issue_fix/create_table_in_down_code/create_table_in_down_code.php");
+    //     $this->deleteTablesForCreateTableInDownCode();
+    //     $this->createTableForCreateTableInDownCode();
+    //     $this->runGenerator($testFile, 'mysql');
+    //     // $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+    //     //     'recursive' => true,
+    //     // ]);
+    //     // $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/issue_fix/create_table_in_down_code/mysql/app"), [
+    //     //     'recursive' => true,
+    //     // ]);
+    //     // $this->checkFiles($actualFiles, $expectedFiles);
+    //     // $this->runActualMigrations('mysql', 1);
+    // }
+
+    // private function deleteTablesForCreateTableInDownCode()
+    // {
+    //     Yii::$app->db->createCommand('DROP TABLE IF EXISTS {{%fruits}}')->execute();
+    //     Yii::$app->db->createCommand('DROP TABLE IF EXISTS {{%animals}}')->execute();
+    // }
+
+    // private function createTableForCreateTableInDownCode()
+    // {
+    //     Yii::$app->db->createCommand()->createTable('{{%fruits}}', [
+    //         'id' => 'pk',
+    //         'colourName' => 'varchar(255)',
+    //     ])->execute();
+    //     Yii::$app->db->createCommand()->createTable('{{%animals}}', [
+    //         'id' => 'pk',
+    //         'colourName' => 'varchar(255)',
+    //     ])->execute();
+    // }
 }
diff --git a/tests/unit/MigrationsGeneratorTest.php b/tests/unit/MigrationsGeneratorTest.php
index 7d14479e..440502a9 100644
--- a/tests/unit/MigrationsGeneratorTest.php
+++ b/tests/unit/MigrationsGeneratorTest.php
@@ -98,7 +98,11 @@ public function simpleDbModelsProvider():array
         $expect = new MigrationModel($dbModel, true, null, [
             'dependencies' => [],
             'upCodes' => [
-                "\$this->createTable('{{%dummy}}', $codes);",
+                '$this->createTable(\'{{%dummy}}\', [
+                    \'id\' => $this->primaryKey(),
+                    \'title\' => $this->string(60)->notNull(),
+                    \'article\' => $this->text()->null(),
+                ]);',
                 "\$this->createIndex('dummy_title_index', '{{%dummy}}', 'title', false);",
                 "\$this->createIndex('dummy_article_hash_index', '{{%dummy}}', 'article', 'hash');",
                 "\$this->createIndex('dummy_article_key', '{{%dummy}}', 'article', true);",
@@ -138,17 +142,14 @@ public function simpleDbModelsProviderForNonMysqlDb():array
                 'dummy_article_key' => DbIndex::make('dummy', ['article'], null, true),
             ]
         ]);
-        $codes = str_replace(PHP_EOL,
-            PHP_EOL . MigrationRecordBuilder::INDENT,
-            VarDumper::export([
-                'id' => '$this->primaryKey()',
-                'title' => '$this->string(60)->notNull()',
-                'article' => '$this->text()->null()->defaultValue("")',
-            ]));
         $expect = new MigrationModel($dbModel, true, null, [
             'dependencies' => [],
             'upCodes' => [
-                "\$this->createTable('{{%dummy}}', $codes);",
+                '$this->createTable(\'{{%dummy}}\', [
+                    \'id\' => $this->primaryKey(),
+                    \'title\' => $this->string(60)->notNull(),
+                    \'article\' => $this->text()->null()->defaultValue(""),
+                ]);',
                 "\$this->createIndex('dummy_title_index', '{{%dummy}}', 'title', false);",
                 "\$this->createIndex('dummy_article_hash_index', '{{%dummy}}', 'article', 'hash');",
                 "\$this->createIndex('dummy_article_key', '{{%dummy}}', 'article', true);",
diff --git a/tests/unit/XDbDefaultExpressionTest.php b/tests/unit/XDbDefaultExpressionTest.php
new file mode 100644
index 00000000..ee07bae5
--- /dev/null
+++ b/tests/unit/XDbDefaultExpressionTest.php
@@ -0,0 +1,208 @@
+<?php
+
+namespace tests\unit;
+
+use cebe\yii2openapi\generator\ApiGenerator;
+use tests\DbTestCase;
+use Yii;
+use yii\db\mysql\Schema as MySqlSchema;
+use yii\db\pgsql\Schema as PgSqlSchema;
+use yii\helpers\FileHelper;
+use yii\helpers\VarDumper;
+use function array_filter;
+use function getenv;
+use function strpos;
+
+class XDbDefaultExpressionTest extends DbTestCase
+{
+    public function testSimple()
+    {
+        // default DB is Mysql ------------------------------------------------
+        $this->deleteTables();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php");
+        $this->runGenerator($testFile, 'mysql');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_maria_db', 'migrations_pgsql_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/mysql/simple/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('mysql', 1);
+
+        // see https://mariadb.com/kb/en/timestamp/#examples
+        // Only the first timestamp is automatically inserted and updated, other will have value default '0000-00-00 00:00:00'
+        $this->changeDbToMariadb();
+        $this->deleteTables();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php");
+        $this->runGenerator($testFile, 'maria');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_mysql_db', 'migrations_pgsql_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/maria/simple/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('maria', 1);
+
+        $this->changeDbToPgsql();
+        $this->deleteTables();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.php");
+        $this->runGenerator($testFile, 'pgsql');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_mysql_db', 'migrations_maria_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/pgsql/simple/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('pgsql', 1);
+    }
+
+    private function deleteTables()
+    {
+        Yii::$app->db->createCommand('DROP TABLE IF EXISTS {{%fruits}}')->execute();
+    }
+
+    public function testEdit()
+    {
+        // default DB is Mysql ------------------------------------------------
+        $this->deleteTables();
+        $this->createTablesForEdit();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php");
+        $this->runGenerator($testFile, 'mysql');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_maria_db', 'migrations_pgsql_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/mysql/edit/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('mysql', 1);
+
+        $this->changeDbToMariadb();
+        $this->deleteTables();
+        $this->createTablesForEdit();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php");
+        $this->runGenerator($testFile, 'maria');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_mysql_db', 'migrations_pgsql_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/maria/edit/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('maria', 1);
+
+        $this->changeDbToPgsql();
+        $this->deleteTables();
+        $this->createTablesForEdit();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.php");
+        $this->runGenerator($testFile, 'pgsql');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_mysql_db', 'migrations_maria_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/pgsql/edit/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('pgsql', 1);
+    }
+
+    private function createTablesForEdit()
+    {
+        Yii::$app->db->createCommand()->createTable('{{%fruits}}', [
+            'ts' => 'datetime',
+            'ts2' => 'datetime',
+            'ts3' => 'datetime',
+            'ts4' => 'timestamp',
+            'ts5' => 'timestamp',
+            'ts6' => 'timestamp',
+            'd' => 'date',
+            'd2' => 'text',
+            'd3' => 'text',
+            'ts7' => 'date',
+        ])->execute();
+    }
+
+    public function testEditExpression()
+    {
+        // default DB is Mysql ------------------------------------------------
+        $this->deleteTables();
+        $this->createTablesForEditExpression();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php");
+        $this->runGenerator($testFile, 'mysql');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_maria_db', 'migrations_pgsql_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/mysql/edit_expression/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('mysql', 1);
+
+        $this->changeDbToMariadb();
+        $this->deleteTables();
+        $this->createTablesForEditExpression();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/mysql/x_db_default_expression_mysql.php");
+        $this->runGenerator($testFile, 'maria');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_mysql_db', 'migrations_pgsql_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/maria/edit_expression/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('maria', 1);
+
+        $this->changeDbToPgsql();
+        $this->deleteTables();
+        $this->createTablesForEditExpression();
+        $testFile = Yii::getAlias("@specs/x_db_default_expression/pgsql/x_db_default_expression_pgsql.php");
+        $this->runGenerator($testFile, 'pgsql');
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+            'except' => ['migrations_mysql_db', 'migrations_maria_db']
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/x_db_default_expression/pgsql/edit_expression/app"), [
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations('pgsql', 1);
+    }
+
+    private function createTablesForEditExpression()
+    {
+        $mysqlColumns = [
+            'ts' => 'datetime DEFAULT \'2011-11-11 00:00:00\'',
+            'ts2' => 'datetime DEFAULT CURRENT_TIMESTAMP',
+            'ts3' => 'datetime DEFAULT CURRENT_TIMESTAMP',
+            'ts4' => 'timestamp DEFAULT CURRENT_TIMESTAMP',
+            'ts5' => 'timestamp DEFAULT \'2011-11-11 00:00:00\'',
+            'ts6' => 'timestamp DEFAULT CURRENT_TIMESTAMP',
+            'd' => 'date DEFAULT \'2011-11-11\'',
+            'd2' => 'text', // DEFAULT "2011-11-11"
+            'd3' => 'text', // DEFAULT CURRENT_DATE + INTERVAL 1 YEAR
+            'ts7' => 'date DEFAULT \'2011-11-11\'',
+
+            // https://github.com/yiisoft/yii2/issues/19747
+            // 'ts8' => 'date DEFAULT (CURRENT_DATE + INTERVAL 2 YEAR)',
+        ];
+        if (ApiGenerator::isPostgres()) {
+            $pgsqlColumns = $mysqlColumns;
+            $pgsqlColumns['ts7'] = 'date DEFAULT \'2011-11-11\'';
+            Yii::$app->db->createCommand()->createTable('{{%fruits}}', $pgsqlColumns)->execute();
+            return;
+        }
+
+        Yii::$app->db->createCommand()->createTable('{{%fruits}}', $mysqlColumns)->execute();
+    }
+}