来自3个表的SQL报告，其中包含字段的SUM

Question

我有3张桌子看图片

我想要的sql语句，其产生的报告类似于pic中的“必需报告”。

Answer 1

如果amount对借记交易为负，则会更容易。 而且，余额是credit - debit ，而不是debit - credit 。 任何状况之下：

SELECT Userid, UserName, Dep_title,
       ( (SELECT COALESCE(SUM(amount), 0) FROM Transctions WHERE userid = USER.userid AND tr_type = 'Credit')
       - (SELECT COALESCE(SUM(amount), 0) FROM Transctions WHERE userid = USER.userid AND tr_type = 'Debit')
       ) AS Balance
  FROM USER
  JOIN Department USING (dep_id)

Answer 2

你可以尝试这样的事情：

SELECT
  u.Userid AS Userid,
  u.UserName AS UserName,
  d.Dep_title AS Dep_title,
  SUM(IF(t.tr_type='Credit',-1*t.amount,t.amount)) AS "Balance(Debit-Credit)"
FROM USER AS u
LEFT JOIN Departement AS d USING(dep_id)
LEFT JOIN Transactions AS t ON u.Userid=t.userid
GROUP BY u.Userid

Answer 3

我认为您要查询的是...

SELECT Userid,
       UserName,
       (SELECT Dep_title
            FROM department
            WHERE USER.dep_id = department.dep_id) AS Dep_title,
       ((SELECT (SUM(amount)
             FROM Transactions
             WHERE Transactions.userid = USER.Userid AND
                   tr_type             = 'Credit') -
        (SELECT (SUM(amount)
             FROM Transactions
             WHERE Transactions.userid = USER.Userid AND
                   tr_type             = 'Debit')) AS "Balance(Debit-Credit)"
    FROM USER;

如果可以允许我进行一些观察； 首先，您的最后一列标题似乎没有反映出该列的内容，其次，表和列名的随意大写会在将来带来很多麻烦； 我建议您使用一致的样式进行大写和缩写形式。

Answer 4

这应该可以工作（不需要子选择，但这未经测试）：

SELECT
  USER.Userid,
  USER.UserName,
  Department.Dep_title,
  SUM(IF(Transactions.tr_type='Credit',amount,amount*(-1))) as Balance
FROM
  USER,
  Department,
  Transactions
WHERE
  USER.Userid = Transactions.userid
AND
  USER.dep_id = Department.dep_id
GROUP BY
  USER.Userid

Answer 5

Select U.UserId, U.Username, D.Dep_Title
    , Coalesce(Sum( Case When T.tr_type = 'Debit' Then -1 Else 1 End * T.Amount )
            ,0) As [Balance (Debit-Credit)]
From Users As U
    Join Department As D
        On D.Dep_Id = U.Dep_Id
    Left Join Transactions As T
        On T.UserId = U.UserId
Group By U.UserId, U.Username, D.Dep_Title

Answer 6

我尚未对此进行测试，但是您应该可以使用IF语句计算出贷方之间的差额。

SELECT u.Userid, u.UserName, d.Dep_title, t.Balance
FROM USER As u
    LEFT JOIN Department AS d on u.dep_id = d.dep_id
    LEFT JOIN (SELECT userid, SUM(IF(tr_type = 'Debit', amount, -1*amount)) AS Balance FROM Transactions GROUP BY userid) AS t