我如何获得第四列的

这一语句将产生一个4列的表的总和：我如何获得第四列的

SELECT shipped.badguy AS badguy, shipped.sdate AS LineDate, 
     'Delivery' AS Legend, -price*quantity AS amount 
    FROM product JOIN shipped ON (product.id = shipped.product) 
UNION 
    SELECT receipt.badguy, receipt.rdate,notes, amount 
    FROM receipt

如何获得上述产生什么样的列第4的总和？

来源

2010-03-16 l--' ' ' ' ' ' ---------' ' ' ' ' ' ' ' ' ' ' '

哪个数据库？ – 2010-03-16 21:48:25

您的查询似乎不完整。 – 2010-03-16 21:49:30

我喜欢使用子查询的一切。

SELECT SUM(results.amount) 
FROM 
(
SELECT -price*quantity AS amount 
    FROM product JOIN shipped ON (product.id = shipped.product) 
UNION 
    SELECT amount 
    FROM 
... 
) results

来源

2010-03-16 21:44:22

sql：error每个派生表都必须有自己的别名 number：1248 – 2010-03-16 21:47:48

哦，是的，你需要一个子查询的别名。我会添加它。 – 2010-03-16 21:56:01

在Oracle中，子查询表达式不需要别名。 'select count（dummy）from（select * from dual）;'是完全有效的。 – 2010-03-16 22:22:53

SUM(-price*quantity)

呵呵？

来源

2010-03-16 21:41:49 zerkms

尝试

sum(price*quantity)

或两个查询合并为

SELECT badguy,rdate,notes,SUM(AMOUNT) FROM(
     SELECT shipped.badguy AS badguy, shipped.sdate AS LineDate, 
     'Delivery' AS Legend, -price*quantity AS amount 
    FROM product JOIN shipped ON (product.id = shipped.product) 
UNION 
    SELECT receipt.badguy, receipt.rdate,notes, amount 
    FROM) A

来源

2010-03-16 21:41:53

将您的查询包裹在另一个查询中，其中外部查询只获取所需的总和。这使您的查询子查询。

SELECT SUM(amount) FROM (
    SELECT shipped.badguy AS badguy, shipped.sdate AS LineDate, 
      'Delivery' AS Legend, -price*quantity AS amount 
     FROM product JOIN shipped ON (product.id = shipped.product) 
    UNION 
    SELECT receipt.badguy, receipt.rdate,notes, amount 
    FROM <...> 
)

来源

2010-03-16 21:49:34

我如何获得第四列的

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