加入子查询

Question

我有4张桌子

1. members(id, name, milk_no, ...)
2. collections(id, member_id, amount, date, ...)
3. credit_payment_transaction(id, member_id, amount, date, ...)
4. deductions(id, member_id, amount, date, ...)

我正在尝试为每个成员提供一个返回的查询。

milk_no | totalDeduction  | totalStore | totalCollection

结果应仅返回totalDeduction | totalStore | totalCollection

中至少一个的成员

这就是我想出来的

SELECT members.milk_no, memberCollections.totalCollection, stores.totalStore, memberDeductions.totalDeduction
FROM members
LEFT JOIN 
   (SELECT SUM(amount) AS totalCollection, member_id 
    FROM collections 
    GROUP BY member_id) AS memberCollections
    ON memberCollections.member_id = members.id

LEFT JOIN 
   (SELECT SUM(amount) AS totalStore, member_id 
    FROM credit_payment_transaction 
    GROUP BY member_id) AS stores
    ON stores.member_id = members.id        

LEFT JOIN 
   (SELECT SUM(amount) AS totalDeduction, member_id 
    FROM deductions 
    GROUP BY member_id) AS memberDeductions
    ON memberDeductions.member_id = members.id

以上查询返回此

此结果的问题是，它包含不需要的数据（具有3个空值的数据）。当我更改为RIGHT JOIN时，根本不会返回任何结果。

Answer 1

只需在查询底部添加WHERE子句：

WHERE totalCollection IS NOT NULL OR totalStore IS NOT NULL OR totalDeduction IS NOT NULL

您可以像这样简化查询：

SELECT m.id, SUM(c.amount) AS totalCollection, SUM(cpt.amount) AS totalStore, SUM(d.amount) AS totalDeduction
FROM members m
LEFT JOIN collections c ON m.id = c.member_id
LEFT JOIN credit_payment_transaction cpt ON m.id = cpt.member_id
LEFT JOIN deductions d ON m.id = d.member_id
GROUP BY m.id
HAVING SUM(c.amount) > 0 OR  SUM(cpt.amount) > 0 OR SUM(d.amount) > 0

此查询也将消除成员重复