DQL - 综合练习

1. 查询年龄为 20,21,22,23 岁的女员工信息。

select * from emp where gender='女' and age between 20 and 23;
select * from emp where gender='女' and age in(20,21,22,23);
select * from emp where gender='女' and age=20 or age=21 or age=22 or age=23;

2. 查询性别为 男 ，并且年龄在 20-40 岁(含)以内的姓名为三个字的员工。

select name,age,gender from emp where gender='男' and (age between 20 and 40) and name like '___';

3. 统计员工表中,年龄小于 60 岁的，男性员工和女性员工的人数。

select gender,count(*) as empCount from emp where age < 60 group by gender;

4. 查询所有年龄小于等于 35 岁员工的姓名和年龄，并对查询结果按年龄升序排序，如果年龄相同按入职时间降序排序。

select name,age from emp where age <= 35 order by  age asc, entrydate desc;

5. 查询性别为男，且年龄在 20-40 岁(含)以内的前 5 个员工信息，对查询的结果按年龄升序排序，年龄相同按入职时间升席排序

select * from emp where gender = '男' and (age between 20 and 40) order by age asc, entrydate asc limit 0,5;