题目描述

从titles表获取按照title进行分组，每组个数大于等于2，给出title以及对应的数目t。
CREATE TABLE IF NOT EXISTS "titles" (
`emp_no` int(11) NOT NULL,
`title` varchar(50) NOT NULL,
`from_date` date NOT NULL,
`to_date` date DEFAULT NULL);

输入描述:

无

输出描述:

title	t
Assistant Engineer	2
Engineer	4
省略	省略
Staff	3

SQL:

select title,count(title) as t from titles
group by title having t>=2

　　用count和group by 统计同一条数据