sql - 计算属于特定类型的条目

Question

假设我有一个名为people 的数据库:

有 id 和 type

我如何计算属于特定类型的人。

我不想有这样的查询，我想自动执行此操作:

SELECT 
         COUNT(CASE WHEN type = 'single' THEN 1 END) as single,
         COUNT(CASE WHEN type = 'married' THEN 1 END) as marrried,
         COUNT(CASE WHEN type = 'kids' THEN 1 END) as kids
         ......
FROM people;

我该怎么做？谢谢

Answer 1

使用分组依据

SELECT COUNT(id), type FROM people GROUP BY  type