数据库sql语句

去重

selECT distinct university  from user_profile;

范围between

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;

排除某个条件查其他

select device_id,gender,age,university from user_profile where university <> "复旦大学"
<>除了
select device_id,gender,age,university from user_profile where university not in "复旦大学"
select device_id,gender,age,university from user_profile where university != "复旦大学"

排序：order by

默认升序asc
select device_id ,age   from  user_profile order by age 
select device_id ,gpa,age from user_profile order by gpa ,age
select device_id ,gpa ,age from  user_profile order  by gpa, age asc
select device_id ,gpa ,age from  user_profile order  by gpa asc, age asc
降序desc
select device_id ,gpa ,age from  user_profile order  by gpa, age desc
select device_id ,gpa ,age from  user_profile order  by gpa desc, age desc

分组查询：group by