MYSQL常用语句

limit--查询结果限制返回n行

select * from table_name limit n;  #n代表行数

group by--查询结果去重

select id from table_name group by id;  

select name1 as name2--将查询后的列重新命名

select device_id as user_infos_example from user_profile limit 2;

order by name--查找后排序

select device_id, age from user_profile order by age;

order by name1, name2--多列排序(asc升序，desc降序)

select device_id, gpa, age from user_profile order by gpa asc, age asc;  

between age1 and age2 或者 >=age1 and <= age2 或者 age in ('1', '2', '3')--查找某个年龄段的用户信息

select device_id, gender, age from user_profile where age between 20 and 23;

select device_id, gender, age from user_profile where age >= 20 and age <= 23;

不为空 age != '' 或者 age is not NULL

like-- 模糊查询

select device_id, age, university from user_profile where  university like '%北京%';