ERROR 1111（HY000）：在MySQL Cluster 7.3

Question

select count(*) from student 
group by branch

这个查询对我来说非常合适，我得到了这样的输出。

+----------+
| count(*) |
+----------+
|       32 |
|       27 |
|       50 |
|       52 |
|       58 |
|       57 |
|       59 |
+----------+

7行（0.00秒） 但是当我使用

时

select max(count(*)) from student group by branch;

导致错误

  

错误1111：无效使用群组功能

请帮帮我。

我正在使用MySQL Cluster 7.3

Answer 1

您无法嵌套聚合函数。您需要使用子查询。

SELECT MAX(c) 
FROM (SELECT COUNT(*) AS c
      FROM student
      GROUP BY branch) AS t1

Answer 2

您可以使用以下

SELECT COUNT(*) AS total FROM student GROUP BY branch ORDER BY total DESC LIMIT 1

或

将您当前的查询用作子查询

SELECT MAX(t.total) FROM (SELECT COUNT(*) AS total FROM student GROUP BY branch) AS t