简单SQL询问 - MS-SQL Server / 基础类

A (a1,a2,a3) B表也是如此 ,查询A表中不在B表的记录

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有没有主键呀？

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引用

有没有主键呀？

没有

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靠啊没人回答么

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都吃饭去了
我也去了

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select a.a1,a.a2,a.a3,b.a1 from A a
left outer join B b on a.a1=b.al and a.a2=b.a2 and a.a3=b.a3
where isnull(b.al,'')=''

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SELECT A.a1,A.a2,A.a3
from A LEFT OUTER JOIN B ON A.a1=B.a1 AND A.a2=B.a2 AND A.a3=B.a3
WHERE B.a1 is null AND B.a2 is null AND B.a3 is null

试试这样查询

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SQL code:


create table a(a1 varchar(100),a2 varchar(100),a3 varchar(100))

create table b(a1 varchar(100),a2 varchar(100),a3 varchar(100))

insert a
select '1','a','aaa' union all
select '2','b','bbb' union all
select '3','v','vvv' union all
select '4','d','ddd' union all
select '5','c','ccc' union all
select '6','e','eee' union all
select '7','f','fff'

insert b
select '4','d','ddd' union all
select '5','c','ccc' union all
select '6','e','eee' union all
select '10','t','ttt' union all
select '11','y','yyy'

select a.a1,a.a2,a.a3 from a
left outer join b on a.a1=b.a1 and a.a2=b.a2 and a.a3=b.a3
where isnull(b.a1,'')=''

drop table a
drop table b

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SQL code: