表A
字段a1 a2 a3
记录aa 1 123
bb 3 3434
cc 2 dfdsf表B
字段B1 B2 B3
记录bb 1 343
aa 2 fdfd
表A的a2和表B的B2关联
需要查询的结果如下
1 aa 123 bb 343
2 cc dfdsf aa fdfd
3 bb 3434
字段a1 a2 a3
记录aa 1 123
bb 3 3434
cc 2 dfdsf表B
字段B1 B2 B3
记录bb 1 343
aa 2 fdfd
表A的a2和表B的B2关联
需要查询的结果如下
1 aa 123 bb 343
2 cc dfdsf aa fdfd
3 bb 3434
a.a1,a.a2,a.a3,b.b1,b.b3
FROM tb1 AS A
LEFT JOIN tb2 AS B
ON A.a2 = B.b2
LEFT JOIN 表B b
ON a.a2 = b.b2
SELECT
a.a1,a.a2,a.a3,b.b1,b.b3
FROM tb1 AS A
LEFT JOIN tb2 AS B
ON A.a2 = B.b2 up
a.a1,a.a2,a.a3,b.b1,b.b3
FROM tb1 AS A
LEFT JOIN tb2 AS B
ON A.a2 = B.b2
up
-->Author:wufeng4552【水族杰纶】
-->Date :2009-08-28 08:44:50
declare @a table([a1] nvarchar(2),[a2] int,[a3] nvarchar(5))
Insert @a
select N'aa',1,N'123' union all
select N'bb',3,N'3434' union all
select N'cc',2,N'dfdsf'
declare @b table([B1] nvarchar(2),[B2] int,[B3] nvarchar(4))
insert @b
select N'bb',1,N'343' union all
select N'aa',2,N'fdfd'
select
a.[a1],
a.[a2],
a.[a3],
b.[b1],
b.[b3]
from @a a
left join @b b
on A.a2 = B.b2
order by a2
/*
a1 a2 a3 b1 b3
---- ----------- ----- ---- ----
aa 1 123 bb 343
cc 2 dfdsf aa fdfd
bb 3 3434 NULL NULL(3 個資料列受到影響)
*/