SQL 两表联合查询后的结果

2009-08-05 02:30:51 213 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

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一个主表，表结构如下
aid a b c
1 w n m
一个子表，表结构如下，存储主表的主键
id d e f aid
1 p o l 1
2 t y u 1
3 z x h 1
查询子表aid与主表aid相等的记录结果如下
aid a b c d e f
1 w n m p o l
1 w n m t y u
1 w n m z x h
我想要实现的结果为：
aid a b c d e f
1 w n m p o l
t y u
z x h
即：联合查询后重复的值去掉，如何用SQL语句来实现？

...全文

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lqa222

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切换为时间正序

lgqiu2008 2009-08-05

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楼上的强大

ChinaJiaBing 2009-08-05

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declare @tb table (aid int,a nvarchar(10),b nvarchar(10),c nvarchar(10))

insert into @tb  select 1,'w','n','m'

declare @tb1 table (id int,d nvarchar(10),e nvarchar(10),f nvarchar(10),aid int)

insert into @tb1 select 1,'p','o','l',1

     union all   select 2,'t','y','u',1

     union all   select 3,'z','x','h',1

;With China as 

(

select a.*,b.id,b.d,b.e,b.f from @tb a join @tb1 b  on a.aid=b.aid

)

select aid= case when exists(select 1 from china where id<a.id) then '' else a.id  end,

       a= case when exists(select 1 from china where id<a.id) then '' else a end, 

       b= case when exists(select 1 from china where id<a.id) then '' else b  end, 

       c= case when exists(select 1 from china where id<a.id) then '' else c  end,d,e,f 

     from China a

feixianxxx 2009-08-05

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-- =========================================

-- -----------t_mac 小编-------------------

   --------------------希望有天成为大虾---- 

-- =========================================



IF OBJECT_ID('tb1') IS NOT NULL

DROP TABLE tb1

GO

CREATE TABLE tb1( aid int, a varchar(10), b varchar(10) ,c varchar(10))

go

insert tb1 SELECT 

1  ,  'w' , 'n' , 'm' 

go

IF OBJECT_ID('tb2') IS NOT NULL

DROP TABLE tb2

GO

CREATE TABLE tb2( id int, d varchar(10), e varchar(10) ,f varchar(10),aid int)

go

insert tb2 SELECT 

1  ,  'p' , 'o' , 'l'  ,  1 UNION ALL SELECT 

2  ,  't' , 'y' , 'u'  ,  1 UNION ALL SELECT 

3  ,  'z' , 'x' , 'h' ,   1 

go

select rtrim(tb2.aid) as aid ,

a,b,b,

d,e,f

from tb1  join tb2 on tb1.aid=tb2.aid

where id in (select MIN(id) from tb2 group by aid)

union all

select '' ,'','','',d,e,f

from tb2

where id not in (select MIN(id) from tb2 group by aid)

/*

(3 行受影响)

aid          a          b          b          d          e          f

------------ ---------- ---------- ---------- ---------- ---------- ----------

1            w          n          n          p          o          l

                                              t          y          u

                                              z          x          h



*/

--小F-- 2009-08-05

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用isnull来做

SQL77 2009-08-05

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CREATE TABLE TB1(aid  INT,a CHAR,  b CHAR,  c CHAR)

INSERT TB1

SELECT 1   , 'w',  'n',  'm' 



CREATE TABLE TB2(ID  INT,D CHAR,  E CHAR,  F CHAR,AID INT)

INSERT TB2

SELECT 1   , 'P',  'O',  'L' ,1 UNION

SELECT 2   , 'T',  'Y',  'm' ,1 UNION

SELECT 3   , 'Z',  'X',  'm' ,1



--DROP TABLE TB2



SELECT * FROM TB1

SELECT * FROM TB2



SELECT 

CASE WHEN  NOT EXISTS(SELECT 1 FROM TB2  WHERE AID=B.AID AND B.ID>ID) THEN A.AID ELSE NULL END AS AID,

CASE WHEN  NOT EXISTS(SELECT 1 FROM TB2  WHERE AID=B.AID AND B.ID>ID) THEN A ELSE NULL END AS A,

CASE WHEN  NOT EXISTS(SELECT 1 FROM TB2  WHERE AID=B.AID AND B.ID>ID) THEN B ELSE NULL END AS B,

CASE WHEN  NOT EXISTS(SELECT 1 FROM TB2  WHERE AID=B.AID AND B.ID>ID) THEN C ELSE NULL END AS C,

D,E,F 

FROM TB2 B LEFT JOIN TB1 A ON A.AID=B.AID 





AID         A    B    C    D    E    F    

----------- ---- ---- ---- ---- ---- ---- 

1           w    n    m    P    O    L

NULL        NULL NULL NULL T    Y    m

NULL        NULL NULL NULL Z    X    m

lqa222 2009-08-05

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2、3楼的解释都没有实现
不过还是谢谢
哪位大侠帮帮忙啊

SQL77 2009-08-05

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SELECT B.AID ,

CASE WHEN NOT EXISTS(SELECT 1 FROM B T WHERE AID=B.AID AND ID>T.ID) THEN A ELSE NULL END AS A,

CASE WHEN NOT EXISTS(SELECT 1 FROM B T WHERE AID=B.AID AND ID>T.ID) THEN B ELSE NULL END AS B,

CASE WHEN NOT EXISTS(SELECT 1 FROM B T WHERE AID=B.AID AND ID>T.ID) THEN C ELSE NULL END AS C,

D,E,F 

FROM B LEFT JOIN A ON A.AID=B.AID

这样应该行了

SQL77 2009-08-05

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SELECT B.AID ,A,B,C,D,E,F FROM B LEFT JOIN A ON A.AID=B.AID 

AND NOT EXISTS(SELECT 1 FROM B T WHERE AID=B.AID AND ID>T.ID)

??试试

jwdream2008 2009-08-05

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帮顶！期待大侠！

SQL 两表联合查询后的结果

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