Question

我第一次使用SUM并且有以下查询noe：

SELECT Id, Amount, Date, TotalAmount = SUM(Amount) OVER (order by Amount)
FROM Account
WHERE Date >= '2016-03-01' AND Date <= '2016-03-10' AND UserId = 'xyz'
ORDER BY ValutaDate

对于特定用户，TotalAmount应该是整个表的运行总计（因此Sum Over子句应该尊重用户的where子句）。另一方面，我只需要一些记录，而不是整个表，这就是为什么我添加了指定日期范围的where子句。但是现在，当然，我的总和仅根据我指定的范围计算。

我该怎么做，只获得一些由日期范围指定的记录，但得到在整个表格中计算的总和。是否有一种高效的方法来实现这一目标？

先谢谢你帮助我。

Answer 1

首先应用WHERE子句，以便SUM无法访问与之不匹配的行。你可以使用申请。请注意，它将为该用户读取整个表格，因此如果没有合适的索引，可能效果不佳。

SELECT a.Id, a.Amount, a.Date, ta.TotalAmount
FROM Account a
OUTER APPLY (SELECT SUM(CASE WHEN a2.Date <= Account.Date THEN a2.TotalAmount ELSE 0 END) AS TotalAmount FROM Account a2 WHERE a2.UserId = Account.UserId) ta
WHERE a.Date >= '2016-03-01' AND a.Date <= '2016-03-10' AND a.UserId = 'xyz'

Answer 2

将运行总计分解为自己的查询

; WITH all_rows_one_user as (SELECT *
       , TotalAmount = SUM(Amount) OVER (order by ValutaDate) 
    FROM Account
    WHERE UserId = 'xyz')
SELECT Id, Amount, Date, TotalAmount
FROM all_rows_one_user
WHERE Date >= '2016-03-01' AND Date <= '2016-03-10'
ORDER BY ValutaDate

相同的查询，不同的语法：

SELECT Id, Amount, Date, TotalAmount
FROM (SELECT *
       , TotalAmount = SUM(Amount) OVER (order by ValutaDate) 
    FROM Account
    WHERE UserId = 'xyz') AS all_rows_one_user
WHERE Date >= '2016-03-01' AND Date <= '2016-03-10'
ORDER BY ValutaDate

SQL Sum不受where子句约束

2 个答案: