diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3ca23c8ef5..7fa054f56a 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -13416,6 +13416,7 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	List	   *childrels;
 	TupleConstr *attachRel_constr;
 	List	   *partConstraint,
+			   *partConstraintOrig,
 			   *existConstraint;
 	SysScanDesc scan;
 	ScanKeyData skey;
@@ -13581,6 +13582,15 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	partConstraint = list_make1(make_ands_explicit(partConstraint));
 
 	/*
+	 * Adjust the generated constraint to match this partition's attribute
+	 * numbers.  Save the original to be used later if we decide to proceed
+	 * with the validation scan after all.
+	 */
+	partConstraintOrig = copyObject(partConstraint);
+	partConstraint = map_partition_varattnos(partConstraint, 1, attachRel,
+											 rel);
+
+	/*
 	 * Check if we can do away with having to scan the table being attached to
 	 * validate the partition constraint, by *proving* that the existing
 	 * constraints of the table *imply* the partition predicate.  We include
@@ -13715,7 +13725,7 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 			tab = ATGetQueueEntry(wqueue, part_rel);
 
 			/* Adjust constraint to match this partition */
-			constr = linitial(partConstraint);
+			constr = linitial(partConstraintOrig);
 			tab->partition_constraint = (Expr *)
 				map_partition_varattnos((List *) constr, 1,
 										part_rel, rel);
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 13d6a4b747..ec67b4cc73 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -3347,6 +3347,16 @@ ALTER TABLE part_5 DROP CONSTRAINT check_a;
 ALTER TABLE part_5 ADD CONSTRAINT check_a CHECK (a IN (5)), ALTER a SET NOT NULL;
 ALTER TABLE list_parted2 ATTACH PARTITION part_5 FOR VALUES IN (5);
 INFO:  partition constraint for table "part_5" is implied by existing constraints
+-- scan will be skipped, even though partition column attribute numbers differ
+-- from the parent (provided the appropriate check constraint is present)
+CREATE TABLE part_6 (
+	c int,
+	LIKE list_parted2,
+	CONSTRAINT check_a CHECK (a IS NOT NULL AND a = 6)
+);
+ALTER TABLE part_6 DROP c;
+ALTER TABLE list_parted2 ATTACH PARTITION part_6 FOR VALUES IN (6);
+INFO:  partition constraint for table "part_6" is implied by existing constraints
 -- check that the table being attached is not already a partition
 ALTER TABLE list_parted2 ATTACH PARTITION part_2 FOR VALUES IN (2);
 ERROR:  "part_2" is already a partition
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 5dd1402ea6..5779ad1161 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -2178,6 +2178,16 @@ ALTER TABLE part_5 DROP CONSTRAINT check_a;
 ALTER TABLE part_5 ADD CONSTRAINT check_a CHECK (a IN (5)), ALTER a SET NOT NULL;
 ALTER TABLE list_parted2 ATTACH PARTITION part_5 FOR VALUES IN (5);
 
+-- scan will be skipped, even though partition column attribute numbers differ
+-- from the parent (provided the appropriate check constraint is present)
+CREATE TABLE part_6 (
+	c int,
+	LIKE list_parted2,
+	CONSTRAINT check_a CHECK (a IS NOT NULL AND a = 6)
+);
+ALTER TABLE part_6 DROP c;
+ALTER TABLE list_parted2 ATTACH PARTITION part_6 FOR VALUES IN (6);
+
 -- check that the table being attached is not already a partition
 ALTER TABLE list_parted2 ATTACH PARTITION part_2 FOR VALUES IN (2);