从多个表中选择

表A具有ID中，col1

ID COL1 
1  abc 
2  bcd

表B已经COL2，COL3

col2 col3 
bcc abc 
acc bcd

表C具有ID，COL4

ID col3 
1 qwe 
1 tre 
1 uid 
2 jkj 
2 jwekj

现在，我需要选择ID ，COL1，COL2，count（表C中的ID）。样品输出将是

ID COL1 COL2 CNT 
1 abc bcc 3 
2 bcd acc 2

任何人都可以请帮助我吗？表A和B使用CO11和COL3连接。

来源

2012-04-26 Robin clave

什么版本的SQL服务器您使用的是？ – Arion 2012-04-26 07:11:40

SQL Server 2008 – 2012-04-26 07:13:09

为什么标记为PL/SQL？ – 2012-04-26 08:52:08

select a.id 
,  max(a.col1) 
,  avg(b.col2) 
,  count(distinct c.ID) 
from TableA a 
join TableA b 
on  a.col1 = b.col3 
left join 
     TableC c 
on  c.id = a.id 
group by 
     a.id

来源

2012-04-26 07:13:16 Andomar

我们只能通过在id列上进行分组吗？ – 2012-04-26 07:15:47

看看@ Arion的答案 – Andomar 2012-04-26 07:17:15

表A中的所有ID都不需要出现在表C中。所以我需要从Table中获取所有值。如果表C中不存在该ID，则该计数应该为0.这里只有我无法得到它。我尝试了左外连接。但是，仅根据ID进行分组会让我感到厌烦。 – 2012-04-26 07:19:13

为什么不加入表A &表C按ID并获得计数？

SELECT TableA.ID, TableA.COL1, TableB.COL2, COUNT(TableC.*) 
FROM TableA 
INNER JOIN TableB ON TableB.COL3 = TableA.COL1 
INNER JOIN TableC ON TableC.ID = TableA.ID 
GROUP BY TableA.ID, TableA.COL1, TableB.COL2 
ORDER BY TableA.ID, TableA.COL1, TableB.Col2

来源

2012-04-26 07:15:18 Nick

除了从c的id计数为0 – collusionbdbh 2012-07-19 04:37:30

SELECT A.ID, A.COL1, B.COL2, (SELECT COUNT(C.ID) FROM C) AS CNT 
FROM A INNER JOIN B ON A.COL1=B.COL3

来源

2012-04-26 07:15:18

也许是这样的：

SELECT 
    TableA.COL1, 
    TableB.col2, 
    (
     SELECT 
      COUNT(*) 
     FROM 
      TableC 
     WHERE 
      TableC.ID=TableA.ID 
    ) 
FROM 
    TableA 
    JOIN TableB 
     ON TableA.COL1=TableB.col3

来源

2012-04-26 07:15:41 Arion

Select 
    a.Id, a.col1, b.col2, count(c.*) As Cnt 
From A as a 
Inner Join B as b on a.col1 = b.col3 
Inner Join C as c on a.Id = c.Id 
Group By a.Id, a.col1, b.col2

来源

2012-04-26 07:15:43 vvnraman

declare @A table(ID int, col1 varchar(50)) 
declare @B table(col2 varchar(50), col3 varchar(50)) 
declare @C table(ID int, col4 varchar(50)) 

INSERT INTO @A(ID, col1) values(1, 'abc') 
INSERT INTO @A(ID, col1) values(2, 'bcd') 

INSERT INTO @B(col2, col3) values('bcc' , 'abc') 
INSERT INTO @B(col2, col3) values('acc' , 'bcd') 

INSERT INTO @C(ID, col4) values('1' , 'qwe') 
INSERT INTO @C(ID, col4) values('1' , 'tre') 
INSERT INTO @C(ID, col4) values('1' , 'uid') 
INSERT INTO @C(ID, col4) values('2' , 'jkj') 
INSERT INTO @C(ID, col4) values('2' , 'jwekj') 


-- The query 
SELECT a.ID, a.col1, b.col2, (SELECT COUNT(c.ID) FROM @C c WHERE c.ID = a.ID) CNT 
FROM @A a join @b b ON a.col1 = b.col3

来源

2012-04-26 07:26:45

select A.iD, A.Col1,B.col2, 
     (select count(*) from tableC C where C.id=A.ID) as cnt 
from tableA A join tableB B on A.col1=b.col3

来源

2012-04-26 08:10:53 Diego

select A.ID, A.Col1, B.Col2, Count(*) AS Cnt 
from A 
inner join B ON B.Col3 = A.Col1 
left join C ON C.ID = A.ID 
Group By A.ID, A.Col1, B.Col2

来源

2012-05-21 12:04:06

从多个表中选择

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