diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala
index 271ef33090980..8c63cce82ae18 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala
@@ -183,8 +183,7 @@ case class Alias(child: Expression, name: String)(
   }
 
   override def sql: String = {
-    val qualifiersString =
-      if (qualifiers.isEmpty) "" else qualifiers.map(quoteIdentifier).mkString("", ".", ".")
+    val qualifiersString = if (qualifiers.isEmpty) "" else qualifiers.head + "."
     s"${child.sql} AS $qualifiersString${quoteIdentifier(name)}"
   }
 }
@@ -299,8 +298,7 @@ case class AttributeReference(
   override def simpleString: String = s"$name#${exprId.id}: ${dataType.simpleString}"
 
   override def sql: String = {
-    val qualifiersString =
-      if (qualifiers.isEmpty) "" else qualifiers.map(quoteIdentifier).mkString("", ".", ".")
+    val qualifiersString = if (qualifiers.isEmpty) "" else qualifiers.head + "."
     s"$qualifiersString${quoteIdentifier(name)}"
   }
 }