Mysql不同的总和，分组依据

Question

这是我的表：

id  user_id   type   value

1   1         type1     2
2   2         type1     1
3   1         type2     5
4   1         type1     2

我想要这样的输出：

  user_id   type1   type2
    1         4     5
    2         1     0

请帮助

Answer 1

您可以尝试这样：

SELECT 
    user_id, 
    sum( if( type = 'type1', value, 0 ) ) AS type1,  
    sum( if( type = 'type2', value, 0 ) ) AS type2
FROM 
    table_name 
GROUP BY 
    user_id;

Answer 2

我想，这就是你要找的东西：

select 
   user_id,
   (select sum(value) from <yourtablename> sub1 where type = 'type1' where sub1.user_id = baseTable.user_id) as type1,
   (select sum(value) from <yourtablename> sub2 where type = 'type2' where sub2.user_id = baseTable.user_id) as type2,
from
   <yourtablename> baseTable