mysql - 如何在一个查询中使用 sql 条件进行过滤？

Question

很难说我的问题是什么，但我想要的是：

  SELECT name
       , (SELECT count(age) as count) 
    FROM 'students' 
   WHERE class = '1c' 
       ;

  SELECT name
       , (SELECT count(age) as count) 
    FROM 'students' 
   WHERE class = '2b'

它们是 2 个单独的 mysql 句子，那么我该如何在一个句子中进行计数以显示如下内容：

+--------+-------+
| name   | count |
+--------+-------+
| Peeter |   5   |
| Harry  |   3   |
+--------+-------+

标签： mysql

Answer 1

您可以在下面尝试 - 使用group byand inoperator

SELECT name,  count(age) as count
FROM 'students' 
WHERE class in ('1c','2b')
group by name