Question

我的数据库中有记录，如下所示

userid    email    first_name    SUM    Currency_flag
1     abc@gmail.com    User2    8609.00    0   
1     abc@gmail.com    User2      12.00    1
9     xyz@gmail.com    User1      99.00    0
9     xyz@gmail.com    User1     200.00    1
34    qwer@gmail.com   User3     345.00    0
34    qwer@gmail.com   User3     200.00    1
12    dfg@gmail.com    User4       0.00    0
12    dfg@gmail.com    User4     280.00    1

现在我想将它们显示如下

userid   email    first_name      SUM_0     SUM_1
1     abc@gmail.com    User2    8609.00     12.00
9     xyz@gmail.com    User1      99.00    200.00    
34    qwer@gmail.com   User3     345.00    200.00
12    dfg@gmail.com    User4       0.00    280.00

其中sum_0是currency_flag=0时的SUM值，而SUM_1时currency_flag=1是SUM值。

我该怎么做？

Answer 1

试试这个：

SELECT 
`userid`, `email`, `first_name`, 
SUM(IF(`currency_flag`=0, `SUM`, 0)) AS `SUM_0` 
SUM(IF(`currency_flag`=1, `SUM`, 0)) AS `SUM_1` 
FROM `users` 
GROUP BY (`userid`)

Answer 2

这样做的一种方法是自我加入：

SELECT A.UserID, A.Email, A.First_Name, A.SUM AS SUM_0, B.SUM AS SUM_1
  FROM (SELECT *           FROM AnonymousTable WHERE Currency_Flag = 0) AS A
  JOIN (SELECT UserID, SUM FROM AnonymousTable WHERE Currency_Flag = 1) AS B
    ON A.UserID = B.UserID;

Answer 3

select userid,email,first_name,sum(if(currency_flag=0,SUM,0)),sum(if(currency_flag=1,SUM,0)) 
from table 
group by 1

在一条记录下显示多条记录？

3 个答案: