MySQL：将值检索到不同的列中

Question

请看下面的代码。

SELECT Transactions.`idTransactions`,
Transactions.`Transaction_TimeStamp`,
Transactions.`idPortfolio`,
CASE  when Transactions.`Transaction_Amount`< 0  THEN END AS "Encashments"  ELSE END AS "Additions" ,
Portfolio.Activation 
FROM Transactions 
INNER JOIN Portfolio ON Transactions.idPortfolio = Portfolio.idPortfolio 
WHERE Transactions.idPortfolio=1
ORDER BY `Transaction_TimeStamp` DESC

在这里，如果Transactions.Transaction_Amount > 0，那么我需要在“添加”列中显示此值，否则需要在“ Encashment”列中显示此值。 但是我的代码生成错误如下。

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AS "Encashments"  ELSE END AS "Additions" ,
Portfolio.Activation 
FROM Transacti' at line 4 

我该如何解决？

Answer 1

如果要2个不同的列，请使用两种情况

SELECT Transactions.`idTransactions`,
       Transactions.`Transaction_TimeStamp`,
       Transactions.`idPortfolio`,
       CASE when Transactions.`Transaction_Amount` <= 0 
            THEN  (Transaction_Amount*-1)
       END AS Encashments,
       CASE when Transactions.`Transaction_Amount` > 0 
            THEN Transaction_Amount
       END AS Additions,
       Portfolio.Activation 
FROM Transactions 
INNER JOIN Portfolio ON Transactions.idPortfolio = Portfolio.idPortfolio 
WHERE Transactions.idPortfolio=1
ORDER BY `Transaction_TimeStamp` DESC

Answer 2

您的案子没有结果。

CASE  when Transactions.`Transaction_Amount`< 0  THEN something_missing_here END AS

Answer 3

您应该将SQL用作：

SELECT Transactions.`idTransactions`,
Transactions.`Transaction_TimeStamp`,
Transactions.`idPortfolio`,
CASE  when Transactions.`Transaction_Amount`< 0  THEN "Encashments"  ELSE "Additions" END AS Type,
Portfolio.Activation 
FROM Transactions 
INNER JOIN Portfolio ON Transactions.idPortfolio = Portfolio.idPortfolio 
WHERE Transactions.idPortfolio=1
ORDER BY `Transaction_TimeStamp` DESC

您的情况是语法错误。 你可以参考这里