if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(column)
		}
	} else {
		builder.WriteByte('*')
	}
}

// MergeClause merge order by clauses
func (returning Returning) MergeClause(clause *Clause) {
	if v, ok := clause.Expression.(Returning); ok && len(returning.Columns) > 0 {
		if v.Columns != nil {
			returning.Columns = append(v.Columns, returning.Columns...)
		} else {

				stmt.AddVar(writer, nil)
			} else {
				stmt.AddVar(writer, v.GormValue(stmt.Context, stmt.DB))
			}
		case clause.Interface:
			c := clause.Clause{Name: v.Name()}
			v.MergeClause(&c)
			c.Build(stmt)
		case clause.Expression:
			v.Build(stmt)
		case driver.Valuer:
			stmt.Vars = append(stmt.Vars, v)
			stmt.DB.Dialector.BindVarTo(writer, stmt, v)
		case []byte: