SQL Server 在单个查询中对多个表求和

Question

这里是详细信息

表1

rec_id,    rec_amount,       rec_date

1            1500             1/1/2011  
2            4500             1/1/2011  
3            500             1/1/2011  
4            15000             1/1/2011  
5            7500             1/1/2011  

表2

vouc_id       vouc_amount        pay_date
1             15000              1/1/2011
2              750.50            1/1/2011
3              560                1/1/2011

表3

don_id      d_amount           d_date
1           1500                1/1/2011
2             2000              1/1/2011

我需要sum(rec_amount) from tbl1和sum(vouc_amount) from tbl2和sum(d_amount) from tbl3在单个查询中where date = 1/1/2011 。有谁可以帮助我吗？

Answer 1

在表之间使用 union all 并在此基础上进行 SUM

示例

SELECT SUM(TheAmount)
FROM(
SELECT rec_amount AS TheAmount
FROM tbl1
WHERE  rec_date = '20110101'
UNION ALL
SELECT vouc_amount        
FROM tbl2
WHERE  pay_date = '20110101'
UNION ALL
SELECT d_amount           
FROM tbl3
WHERE  d_date = '20110101') x

或彼此相邻

SELECT SUM(rec_amount) AS tbl1Amount,(SELECT SUM(vouc_amount)   
FROM tbl2
WHERE  pay_date = '20110101') AS tbl2Amount ,(SELECT SUM(d_amount)          
FROM tbl3
WHERE  d_date = '20110101')  AS tbl3Amount  
FROM tbl1
WHERE  rec_date = '20110101'