力扣1076(MySQL)-员工项目Ⅱ（简单）

题目：

编写一个SQL查询，报告所有雇员最多的项目。

查询结果格式如下所示：

 解题思路：

方法一：将两个表联结，以project_id进行分组，统计员工数降序排序，然后筛选出第一条数据。

1 select project_id
2 from project a
3 join employee b
4 on a.employee_id = b.employee_id
5 group by project_id
6 order by count(a.employee_id) desc
7 limit 1

方法二:子查询，先查询出最大数，然后在用主查询的统计数等于子查询的最大数。

 1 select project_id
 2 from project_1075 a
 3 group by project_id
 4 having count(employee_id) = (
 5    select count(*) as cout
 6    from project_1075
 7    group by project_id
 8    order by cout desc
 9    limit 1
10 )