select * from(select t.user_name as name ,'接收者' as recive ,t.phone as phone ,t.context as context,t.send_time as sendtime ,t.send_info as sendinfo,x.yw_name as ywname,x.sim_sys as simsysfrom xmkjmas_sms_send_library t ,xmkjmas_code x where x.code=t.yw_codeunion allselect b.user_name as name ,'发送者' as recive,b.phone as phone ,a.context as context,a.receive_time as receive,a.context as context,c.yw_name as ywname ,[color=red]（少了c.sim_sys as simsys）[/color] from xmkjmas_sms_receive_history a,xmkjmas_user b,xmkjmas_code c where a.phone=b.phoneand a.context=c.code)d
错误的原因是列数的个数不一样！~
相关资源：Java 面经手册·小傅哥(公众号：bugstack虫洞栈).pdf
