在同一查询中从借方列减去贷方？答案

【问题标题】：Minus credit from debit column in same query?在同一查询中从借方列减去贷方？
【发布时间】：2013-03-01 16:27:29
【问题描述】：

我有以下查询：

SELECT user_id, SUM( credit ) AS cred, SUM( debit ) AS deb 来自帐户 WHERE user_id = '35'

我想从贷方中减去借方并将其显示在一列中或作为变量中的值显示

【问题讨论】：

【解决方案1】：

这应该可以工作，并且可能比其他两个SUMs 稍快

SELECT a.user_id, 
       a.cred, 
       a.deb, 
       a.deb - a.cred AS value 
FROM   (SELECT user_id, 
               Sum(credit) AS cred, 
               Sum(debit)  AS deb 
        FROM   account 
        WHERE  user_id = '35') a

如果您有多个用户，您可以执行以下操作：

SELECT a.user_id, 
       a.cred, 
       a.deb, 
       a.deb - a.cred AS value 
FROM   (SELECT user_id, 
               Sum(credit) AS cred, 
               Sum(debit)  AS deb 
        FROM   account 
        WHERE  user_id IN (35, 36, 39)
        GROUP BY user_id) a

See the demo

【讨论】：

【解决方案2】：

你可以在同一行计算差异

SELECT  user_id, 
        SUM(credit) AS cred, 
        SUM(debit) AS deb,
        SUM(credit) -  SUM(debit) total
FROM account 
WHERE user_id = 35

更新 1

SELECT  user_id, 
        SUM(credit) AS cred, 
        SUM(debit) AS deb,
        SUM(credit) -  SUM(debit) total
FROM account 
WHERE user_id IN (30,31,32,33,34,35)
GROUP BY user_ID

更新 2

SELECT  user_id, 
        SUM(credit) AS cred, 
        SUM(debit) AS deb,
        SUM(credit) -  SUM(debit) total
FROM account 
WHERE user_id IN (30,31,32,33,34,35)
GROUP BY user_ID
HAVING (SUM(credit) -  SUM(debit)) < 10

【讨论】：

如果我有不同的用户ID怎么办，那么我应该像user_id = '30,31,32,33,34,35'等......
@Akaash 然后你可以使用IN 和GROUP BY。看我的回答。
感谢大家的快速回复。我现在只需要从用户 id 池中选择总数小于 10 的用户 id
total is less than 10 from the pool of users id 是什么意思？
就像我有用户列表，但我只想要该列表中那些总数少于 10 的用户，（减去从贷方中扣除的总金额）