From 8503287ca442ff46c6d0b1204232fc4809012737 Mon Sep 17 00:00:00 2001
From: aviyam181199 <62248413+aviyam181199@users.noreply.github.com>
Date: Sun, 12 Jan 2025 12:18:04 +0200
Subject: [PATCH] Fixed Empty Returning Clause Merge Bug (#7339)

---
 clause/returning.go      |  9 ++++++---
 clause/returning_test.go | 16 ++++++++++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/clause/returning.go b/clause/returning.go
index d94b7a4c..76064c4a 100644
--- a/clause/returning.go
+++ b/clause/returning.go
@@ -26,9 +26,12 @@ func (returning Returning) Build(builder Builder) {
 
 // MergeClause merge order by clauses
 func (returning Returning) MergeClause(clause *Clause) {
-	if v, ok := clause.Expression.(Returning); ok {
-		returning.Columns = append(v.Columns, returning.Columns...)
+	if v, ok := clause.Expression.(Returning); ok && len(returning.Columns) > 0 {
+		if v.Columns != nil {
+			returning.Columns = append(v.Columns, returning.Columns...)
+		} else {
+			returning.Columns = nil
+		}
 	}
-
 	clause.Expression = returning
 }
diff --git a/clause/returning_test.go b/clause/returning_test.go
index bd0ecce8..b7a408ba 100644
--- a/clause/returning_test.go
+++ b/clause/returning_test.go
@@ -26,6 +26,22 @@ func TestReturning(t *testing.T) {
 			}},
 			"SELECT * FROM `users` RETURNING `users`.`id`,`name`,`age`", nil,
 		},
+		{
+			[]clause.Interface{clause.Select{}, clause.From{}, clause.Returning{
+				[]clause.Column{clause.PrimaryColumn},
+			}, clause.Returning{}, clause.Returning{
+				[]clause.Column{{Name: "name"}, {Name: "age"}},
+			}},
+			"SELECT * FROM `users` RETURNING *", nil,
+		},
+		{
+			[]clause.Interface{clause.Select{}, clause.From{}, clause.Returning{
+				[]clause.Column{clause.PrimaryColumn},
+			}, clause.Returning{
+				[]clause.Column{{Name: "name"}, {Name: "age"}},
+			}, clause.Returning{}},
+			"SELECT * FROM `users` RETURNING *", nil,
+		},
 	}
 
 	for idx, result := range results {