mysql 高级查询

• 查询指定字段

select name,age from students;

• 起别名

select name as 姓名,age as 年龄 from students;

select s.name s.age from students as s;

• 去重

select name as 姓名,age as 年龄 from students;

select s.name s.age from students as s;

• 条件查询

--比较运算符.. > < >== 18；
逻辑运算符
--and or not
查看18到28岁之间的所有学生的信息
select* from students
where age>18 and age