时间: 2021-07-31 作者:daque
证明:复构图(只复制构造,源表名:a 新表名:b)sql: select * into b from a where 1<>1证明:正片表(正片数据,源表名:a 目的表名:b)sql: insert into b(a, b, c) select d,e,f from b;证明:表露作品、提交人和结果恢复功夫sql: select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b证明:外贯穿查问(表名1:a 表名2:b)sql: select a.a, a.b, a.c, b.c, b.d, b.f from a left out join b on a.a = b.c证明:议程安置提早五秒钟指示sql:select * from 议程安置 where datediff('minute',f发端功夫,getdate())>5证明:两张关系表,简略主表中仍旧在副表中没有的消息sql:delete from info where not exists ( select * from infobz where info.infid=infobz.infid