这两个个sql语句如何写

[np20000]

a表中有did,a1,a2 字段 b表中有did,b1,b2 字段

1.要选出did在a中有,同时不在b中的字段

2.要按相同did选出did,a1,a2,b1,b2

我只会写foxpro里头的,谁告诉我sqlserver里头怎么写啊,谢谢了,老师

[yelook]

1.select * from a where did not in (select did from b)
或
select a.* from a left join b on a.did=b.did where b.did is null(这个速度要比上面这个快很多)

2.select a.did,a.a1,a.a2,b.b1,b.b2 from a inner join b on a.did=b.did

[伍子V5]

1,select a.* from a,b where a.did<>b.did
2,select a.did,a.a1,a.a2,b.b1,b.b2 from a,b where a.did=b.did

[txlicenhe]

1:
Select did from a where did not in (select did from b)
或
Select a.did from a left join b on a.did = b.did where b.did is null
2:
select a.did,a.a1,a.a2,b.b1,b.b2 from a join b on a.did=b.did

[youngby]

up
关于表的连接建议不要使用WHERE子句，它不是ANSI标准的。
原因看一下执行计划就知道了。

[gmlxf]

1、select did from a where did not in (select did from b)
2、select a.did,a.a1,a.a2,b.b1,b.b2 from a,b where a.did=b.did

[np20000]

回头结贴,谢谢各位