如何在一个查询中获得不同条件下的总和？

Question

如何在一个查询中执行以下操作：

如果我有两个这样的查询

SELECT SUM(value +sal) AS sump
FROM loans 
WHERE active_flag = 1

---

SELECT SUM(value +sal) AS sumn
FROM loans 
WHERE active_flag = 2

---

我希望在同一个查询中获得sump和sumn

Answer 1

SELECT SUM(CASE 
             WHEN active_flag = 1 THEN value + sal 
             ELSE 0 
           END) AS sump,
       SUM(CASE 
             WHEN active_flag = 2 THEN value + sal 
             ELSE 0 
           END) AS sumn 
FROM   loans 
WHERE  active_flag IN ( 1, 2 )