摘要:
找出卡号重复的select card from krs group by card having count(*)>1查询重复语句:select name from krs group by name having count(name) >2一些不错的sql语句,1、说明:复制表(只复制结构,源表 阅读全文
摘要:
三表连接select t1.student, t3.class, t3.reportfrom student t1 left join total t2 on t1.student =t2.studentleft join sub t3 on t2.autoid=t3.masterautoid Le 阅读全文