僅在一個SQL查詢中檢測非規範化數據不一致？

Question

我有兩個表中的非規範化數據。它是非規範化的，因爲從DepositsAndWithdrawals表（下面第二個）我可以獲得當前客戶的餘額，但爲了快速訪問，我將它保存在UserBalance表（下面的第一個表）中，因此我不需要將所有操作時間：

 
+----+----------+---------+ 
| ID | Username | Balance | 
+----+----------+---------+ 
| 1 | Alice | 50  | 
+----+----------+---------+ 
| 2 | Bob  | 20  | 
+----+----------+---------+ 
| 3 | Charles | 30  | 
+----+----------+---------+ 

 
+----+------------+---------+ 
| ID | CustomerID | Amount | 
+----+------------+---------+ 
| 1 | 1   | 50  | 
+----+------------+---------+ 
| 2 | 2   | 80  | 
+----+------------+---------+ 
| 3 | 3   | 10  | 
+----+------------+---------+ 
| 4 | 2   | -60  | 
+----+------------+---------+ 
| 5 | 3   | 20  | 
+----+------------+---------+ 

這帶來了的情況下有系統競爭條件存在一致性問題。因此，爲了檢測這些數據，我希望每天都有一個檢測平衡不一致的DB查詢（即SUM(amount)與balance不同）。如何在單個SQL語句中做這樣的JOIN？

Answer 1

試試這個

SELECT A.ID As customerId, A.BALANCE, SUM(B.AMOUNT) AS REAL_BALANCE FROM A 
JOIN B on A.ID = B.customerId 
GROUP BY A.ID, A.BALANCE 
HAVING SUM(B.AMOUNT) <> A.BALANCE 

哪裏B是您DepositsAndWithdrawals表和A是UserBalance表