mysql - 需要使用两个不同的where子句返回两组数据

Question

我有一个记录交易的表。

表格设置为:

transactions:

id, account_id, budget_id, points, type

我需要返回每个budget_id的type = 'allocation'的积分总和以及type = 'issue'的积分总和

我知道如何在一个查询中执行每一项操作，但不知道如何执行这两项操作。

预期结果集:

budget_id   allocated   issued
   434       200000      100
   242       100000      5020
   621       45000       3940

Answer 1

SELECT budget_id, 
       SUM(IF(type = 'allocation', points, 0)) AS allocated,
       SUM(IF(type = 'issue', points, 0)) AS issued
FROM transactions
GROUP BY budget_id