fix the issue that UnionAll didn't handle the range bump case

Signed-off-by: Yang Keao <[email protected]>
pingcap · Apr 12, 2024 · 1143223 · 1143223
1 parent 0362dc8
commit 1143223
Show file tree

Hide file tree

Showing 3 changed files with 24 additions and 4 deletions.
diff --git a/pkg/planner/core/integration_test.go b/pkg/planner/core/integration_test.go
@@ -30,6 +30,7 @@ import (
 	"github.com/pingcap/tidb/pkg/infoschema"
 	"github.com/pingcap/tidb/pkg/parser/auth"
 	"github.com/pingcap/tidb/pkg/parser/model"
+	"github.com/pingcap/tidb/pkg/parser/mysql"
 	"github.com/pingcap/tidb/pkg/planner/core"
 	"github.com/pingcap/tidb/pkg/sessionctx/variable"
 	"github.com/pingcap/tidb/pkg/table"
@@ -2269,3 +2270,18 @@ func TestIssue48257(t *testing.T) {
 		"└─TableFullScan 1.00 cop[tikv] table:t1 keep order:false",
 	))
 }
+
+func TestIssue52472(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+
+	tk.MustExec("use test")
+	tk.MustExec("CREATE TABLE t1 ( c1 int);")
+	tk.MustExec("CREATE TABLE t2 ( c1 int unsigned);")
+	tk.MustExec("INSERT INTO t1 (c1) VALUES (8);")
+	tk.MustExec("INSERT INTO t2 (c1) VALUES (2454396638);")
+	rs, err := tk.Exec("SELECT c1 FROM t1 UNION ALL SELECT c1 FROM t2")
+	require.NoError(t, err)
+	require.Len(t, rs.Fields(), 1)
+	require.Equal(t, mysql.TypeLonglong, rs.Fields()[0].Column.FieldType.GetType())
+}
diff --git a/pkg/planner/core/logical_plan_builder.go b/pkg/planner/core/logical_plan_builder.go
@@ -1901,7 +1901,7 @@ func unionJoinFieldType(a, b *types.FieldType) *types.FieldType {
 	} else if b.GetType() == mysql.TypeNull {
 		return a
 	}
-	resultTp := types.NewFieldType(types.MergeFieldType(a.GetType(), b.GetType()))
+	resultTp := types.AggFieldType([]*types.FieldType{a, b})
 	// This logic will be intelligible when it is associated with the buildProjection4Union logic.
 	if resultTp.GetType() == mysql.TypeNewDecimal {
 		// The decimal result type will be unsigned only when all the decimals to be united are unsigned.

diff --git a/pkg/types/field_type.go b/pkg/types/field_type.go
@@ -68,7 +68,7 @@ func AggFieldType(tps []*FieldType) *FieldType {
 			currType = *t
 			continue
 		}
-		mtp := MergeFieldType(currType.GetType(), t.GetType())
+		mtp := mergeFieldType(currType.GetType(), t.GetType())
 		isMixedSign = isMixedSign || (mysql.HasUnsignedFlag(currType.GetFlag()) != mysql.HasUnsignedFlag(t.GetFlag()))
 		currType.SetType(mtp)
 		currType.SetFlag(mergeTypeFlag(currType.GetFlag(), t.GetFlag()))
@@ -367,12 +367,16 @@ func DefaultCharsetForType(tp byte) (defaultCharset string, defaultCollation str
 	return charset.CharsetBin, charset.CollationBin
 }
 
-// MergeFieldType merges two MySQL type to a new type.
+// mergeFieldType merges two MySQL type to a new type.
 // This is used in hybrid field type expression.
 // For example "select case c when 1 then 2 when 2 then 'tidb' from t;"
 // The result field type of the case expression is the merged type of the two when clause.
 // See https://github.com/mysql/mysql-server/blob/8.0/sql/field.cc#L1042
-func MergeFieldType(a byte, b byte) byte {
+//
+// This function doesn't handle the range bump: for example, when the unsigned long is merged with signed long,
+// the result should be longlong. However, this function returns long for this case. Please use `AggFieldType`
+// function if you need to handle the range bump.
+func mergeFieldType(a byte, b byte) byte {
 	ia := getFieldTypeIndex(a)
 	ib := getFieldTypeIndex(b)
 	return fieldTypeMergeRules[ia][ib]