sql server 2005错误输出

Question

我有3个表格，向内，发行

Stock table的列和数据：

part_no | part_name | totalqty
10100        ciol      30
112233       abc       20
123456       coper      50

向内表：

part_no | qty
123456   10
123456   20
10100    20
112233   15
10100    25

问题表：

part_no | qty
112233   20
112233   15
123456   10
112233   25
10100    40
10100    20

我想要的输出：

part_no | part_name  |inwardQty |issueQty
10100      coil         45     60
112233     abc          15     60
123456     coper        30     10

以下是我写的查询，但没有给出我想要的输出

select s.part_no,s.part_name,sum(i.qty) as inwardQty,sum(p.qty)as issueQty 
from stock s 
left join inward i on s.part_no = i.part_no
left join issue p on s.part_no = p.part_no 
group by 
    s.part_no,s.part_name

通过此查询获得以下输出：

part_no | part_name  |inwardQty |issueQty
10100      coil         90     120
112233     abc          45     60
123456     coper        30     20

Answer 1

问题在于，您为inward的每个行匹配行issue的每个行，为此他们＆＃39处理相同的部分。我认为子查询在这里最好：

select s.part_no,s.part_name,i.qty as inwardQty,p.qty as issueQty 
from stock s 
left join
    (select part_no,sum(qty) as qty from inward group by part_no) i on s.part_no = i.part_no
left join
    (select part_no,sum(qty) as qty from issue group by part_no) p on s.part_no = p.part_no 

现在，每个联接中只有一行（或零）行加入，并且您不会获得笛卡尔积。

Answer 2

尝试此查询：

SELECT 
    s.part_no, s.part_name,
    InwardQty = (SELECT SUM(qty) FROM @inward i WHERE i.part_no = s.part_no),
    IssueQty = (SELECT SUM(qty) FROM @issue p WHERE p.part_no = s.part_no)
FROM 
    dbo.stock s 
GROUP BY
    s.part_no, s.part_name

给我准确的输出结果。