mysql - 如何按日期分组

Question

下面我无法对下面的数字进行按日期分组。

我尝试将分组依据放在不同的行中，但不起作用。

SELECT SUM(a.NetAmount) AS TotalDonation
FROM (
 SELECT
  (
   CASE WHEN bt.BalanceTransactionCurrencyID = 17
    THEN bt.BalanceTransactionNet
   ELSE
    bt.BalanceTransactionNet * (SELECT TOP 1 ExrateValue FROM Exrate WHERE ExrateDate < bt.BalanceTransactionCreated AND bt.BalanceTransactionCurrencyID = CurrencyID ORDER BY ExrateDate Desc)
   END
  ) AS NetAmount

 FROM Charge as ch

 JOIN BalanceTransaction as bt ON (ch.BalanceTransactionID = bt.BalanceTransactionID)

 WHERE ch.ChargeCreatedDate BETWEEN '3-1-2019' AND '3-31-2019'

) AS a

我想看看:

Days              Total Amount
March 1           xxxx
March 2           xxxx
March 3           xxx

Answer 1

MySQL 不使用TOP。使用LIMIT:

SELECT ChargeCreatedDate, SUM(netamount)
FROM (SELECT ch.ChargeCreatedDate,
             (CASE WHEN bt.BalanceTransactionCurrencyID = 17
                   THEN bt.BalanceTransactionNet
                   ELSE bt.BalanceTransactionNet * (SELECT e.ExrateValue
                                                    FROM Exrate e
                                                    WHERE e.ExrateDate < bt.BalanceTransactionCreated AND
                                                          e.CurrencyID = bt.BalanceTransactionCurrencyID 
                                                    ORDER BY ExrateDate Desc
                                                    LIMIT 1
                                                   )
              END) AS NetAmount
      FROM Charge ch JOIN
           BalanceTransaction bt
           ON ch.BalanceTransactionID = bt.BalanceTransactionID
      WHERE ch.ChargeCreatedDate BETWEEN '2019-03-01' AND '2019-03-31'
     ) chtbt
GROUP BY ChargeCreatedDate;

如果您碰巧使用 SQL Server，则可以将 LIMIT 1 替换为 FETCH FIRST 1 ROW ONLY。