MySQL Query Error, sql: (SELECT sell_id,price,unit,property_sys_select,property_sys_input,img_path,imp_status,update_date FROM web_sell_f WHERE sell_id IN(5493418,5493422)) UNION (SELECT sell_id,price,unit,property_sys_select,property_sys_input,img_path,imp_status,update_date FROM web_sell_b WHERE sell_id IN(18841985,57683504,57682748,57681667,57646444,57646387,57643021,57642308,57571765,57564739)) UNION (SELECT sell_id,price,unit,property_sys_select,property_sys_input,img_path,imp_status,update_date FROM web_sell_6 WHERE sell_id IN(43423415,43423535,43423352,43329659,43330013,43423608,43423704,43596950)), ErrMsg: MySQL server has gone away