Fix gorm.Expr with SubQuery, fix #3857

statement.go

@@ -165,16 +165,7 @@ func (stmt *Statement) AddVar(writer clause.Writer, vars ...interface{}) {
 		case Valuer:
 			stmt.AddVar(writer, v.GormValue(stmt.Context, stmt.DB))
 		case clause.Expr:
-			var varStr strings.Builder
+			v.Build(stmt)
-			var sql = v.SQL
-			for _, arg := range v.Vars {
-				stmt.Vars = append(stmt.Vars, arg)
-				stmt.DB.Dialector.BindVarTo(&varStr, stmt, arg)
-				sql = strings.Replace(sql, "?", varStr.String(), 1)
-				varStr.Reset()
-			}
-
-			writer.WriteString(sql)
 		case driver.Valuer:
 			stmt.Vars = append(stmt.Vars, v)
 			stmt.DB.Dialector.BindVarTo(writer, stmt, v)

tests/create_test.go

@@ -2,6 +2,7 @@ package tests_test
 
 import (
 	"errors"
+	"regexp"
 	"testing"
 	"time"
 
@@ -493,3 +494,26 @@ func TestFirstOrCreateWithPrimaryKey(t *testing.T) {
 		t.Errorf("invalid primary key after creating, got %v, %v", companies[0].ID, companies[1].ID)
 	}
 }
+
+func TestCreateFromSubQuery(t *testing.T) {
+	user := User{Name: "jinzhu"}
+
+	DB.Create(&user)
+
+	subQuery := DB.Table("users").Where("name=?", user.Name).Select("id")
+
+	result := DB.Session(&gorm.Session{DryRun: true}).Model(&Pet{}).Create([]map[string]interface{}{
+		{
+			"name":    "cat",
+			"user_id": gorm.Expr("(?)", DB.Table("(?) as tmp", subQuery).Select("@uid:=id")),
+		},
+		{
+			"name":    "dog",
+			"user_id": gorm.Expr("@uid"),
+		},
+	})
+
+	if !regexp.MustCompile(`INSERT INTO .pets. \(.name.,.user_id.\) .*VALUES \(.+,\(SELECT @uid:=id FROM \(SELECT id FROM .users. WHERE name=.+\) as tmp\)\),\(.+,@uid\)`).MatchString(result.Statement.SQL.String()) {
+		t.Errorf("invalid insert SQL, got %v", result.Statement.SQL.String())
+	}
+}