fix: count() when use group by and only find one record (#4885)

Co-authored-by: 李龙 <lilong.21@bytedance.com>

finisher_api.go

@@ -419,9 +419,11 @@ func (db *DB) Count(count *int64) (tx *DB) {
 
 	tx.Statement.Dest = count
 	tx = tx.callbacks.Query().Execute(tx)
-	if tx.RowsAffected != 1 {
+
+	if _, ok := db.Statement.Clauses["GROUP BY"]; ok || tx.RowsAffected != 1 {
 		*count = tx.RowsAffected
 	}
+
 	return
 }
 

tests/count_test.go

@@ -134,4 +134,15 @@ func TestCount(t *testing.T) {
 		t.Fatalf("Count should be 3, but got count: %v err %v", count10, err)
 	}
 
+	var count11 int64
+	sameUsers := make([]*User, 0)
+	for i := 0; i < 3; i++ {
+		sameUsers = append(sameUsers, GetUser("count-4", Config{}))
+	}
+	DB.Create(sameUsers)
+
+	if err := DB.Model(&User{}).Where("name = ?", "count-4").Group("name").Count(&count11).Error; err != nil || count11 != 1 {
+		t.Fatalf("Count should be 3, but got count: %v err %v", count11, err)
+	}
+
 }

tests/go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/lib/pq v1.10.4
 	golang.org/x/crypto v0.0.0-20211117183948-ae814b36b871 // indirect
 	gorm.io/driver/mysql v1.2.0
-	gorm.io/driver/postgres v1.2.2
+	gorm.io/driver/postgres v1.2.3
 	gorm.io/driver/sqlite v1.2.6
 	gorm.io/driver/sqlserver v1.2.1
 	gorm.io/gorm v1.22.3