mysql - 需要用两个不同的 where 子句返回两组数据

Question

我有一张记录交易记录的表格。

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' 点总和和 type = 'issue' 点总和

我知道如何在一个查询中执行每一项，但不知道如何同时执行这两项。

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