Query Error: select a.*,(select begindate from redclass.qa_line_date where line_id=a.id and begindate>'2024-12-23' and state=0 order by begindate limit 1) as begindate from redclass.qa_line a where (a.publish_wait=0 and a.is_stop=0) order by paixu,id desc limit 0,15 MySQL server has gone away