在同一個查詢中從借方列減去貸方？

Question

我有以下查詢：

SELECT USER_ID，SUM（信用）AS可信度，SUM（借記卡）AS DEB 從帳戶 其中USER_ID = '35'

我想減去借記信貸和表演它在一列或作爲可變

Answer 1

的值就可以計算出在同一行中的差

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

UPDATE 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 

Answer 2

這應該工作，並很可能略快於做其他兩種SUM小號

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 

如果你有多個用戶，你可以這樣做如：

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