Fix Count with order by for PostgreSQL

finisher_api.go

@@ -321,16 +321,23 @@ func (db *DB) Count(count *int64) (tx *DB) {
 				expr = clause.Expr{SQL: "COUNT(?)", Vars: []interface{}{clause.Column{Name: dbName}}}
 			}
 		}
-
 		tx.Statement.AddClause(clause.Select{Expression: expr})
 		defer tx.Statement.AddClause(clause.Select{})
 	}
 
+	// Count without ORDER BY for PostgreSQL
+	orderBy := tx.Statement.Clauses["ORDER BY"]
+	delete(tx.Statement.Clauses, "ORDER BY")
+	defer func() {
+		tx.Statement.Clauses["ORDER BY"] = orderBy
+	}()
+
 	tx.Statement.Dest = count
 	tx.callbacks.Query().Execute(tx)
 	if tx.RowsAffected != 1 {
 		*count = tx.RowsAffected
 	}
+
 	return
 }
 

tests/count_test.go

@@ -36,9 +36,12 @@ func TestCount(t *testing.T) {
 		t.Errorf("Count() method should get correct value, expect: %v, got %v", count, len(users))
 	}
 
-	if err := DB.Model(&User{}).Where("name = ?", user1.Name).Order("id desc").Count(&count).Find(&users).Error; err != nil {
+	if err := DB.Model(&User{}).Where("id in ?", []uint{user1.ID, user2.ID, user3.ID}).Order("id DESC").Count(&count).Find(&users).Error; err != nil {
 		t.Errorf(fmt.Sprintf("Count with order by should work, but got err %v", err))
 	}
+	if users[0].ID != user3.ID {
+		t.Errorf(fmt.Sprintf("Find order by after Count, first item should id: %d, but got id: %d", user3.ID, users[0].ID))
+	}
 
 	DB.Model(&User{}).Where("name = ?", user1.Name).Count(&count1).Or("name in ?", []string{user2.Name, user3.Name}).Count(&count2)
 	if count1 != 1 || count2 != 3 {

tests/go.mod

@@ -7,9 +7,9 @@ require (
 	github.com/jinzhu/now v1.1.1
 	github.com/lib/pq v1.6.0
 	gorm.io/driver/mysql v1.0.2
-	gorm.io/driver/postgres v1.0.2
+	gorm.io/driver/postgres v1.0.3
 	gorm.io/driver/sqlite v1.1.3
-	gorm.io/driver/sqlserver v1.0.4
+	gorm.io/driver/sqlserver v1.0.5
 	gorm.io/gorm v1.20.2
 )