IF条件下的MYSQL求和查询

Question

我正在为SUM上的多个IF条件的报表构建查询.我在SUM上有多个IF条件时遇到问题.

这是查询:

SELECT SUM(`totalamount`) AS Total, 
SUM(`PayPalFee`) AS Fees,
DATE(`TransactionDate`) AS `Day`, 
SUM(IF(PaymentType = "paypal", 1,0)) AS Paypal, 
SUM(IF(PaymentType = "check", 1,0)) AS Checks, 
SUM(IF(PaymentType = "credit card", 1,0)) AS CreditCard, 
COUNT(*) AS Entries
 FROM my_table
 WHERE TransactionDate between '2011-05-05' AND '2012-01-30'
 GROUP BY day
 ORDER BY `day` ASC

这个查询工作得很好.

当我尝试添加以下条件SUM语句时:

 SUM('TotalAmount'(PaymentType = "credit card", 1,0)) AS CreditCardTotal,

此条件IF语句失败.

我有一个名为'TotalAmount'的列和一个名为'PaymentType'的列我希望每天创建信用卡交易的SUM,每天检查交易的总和,每天的paypal交易的总和.我试图创建一个子查询,但这会返回整个TotalAmount列的值,而不是按天分解.

Answer 1

以这种方式尝试使用CASE:

SUM(CASE 
    WHEN PaymentType = "credit card" 
    THEN TotalAmount 
    ELSE 0 
END) AS CreditCardTotal,

应该给你想要的东西......

Answer 2

这个怎么样？

SUM(IF(PaymentType = "credit card", totalamount, 0)) AS CreditCardTotal