请问mysql的delete语句直接用in(1,2,3)作为条件为什么只删除一条记录？


public int Delete(string ids)
        {
            string sql = string.Format("DELETE FROM {0} WHERE ID IN (?ids)",_tableName);
            MySqlParameter[] cmdParms = new MySqlParameter[]{
                new MySqlParameter("?ids",MySqlDbType.String)
            };
            cmdParms[0].Value = ids;
          
            return DbHelperMySQL.ExecuteSql(sql,cmdParms);
        }public static int ExecuteSql(string SQLString, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (MySql.Data.MySqlClient.MySqlException e)
                    {
                        throw e;
                    }
                }
            }
        }