MySQL查询

检索表中的所有数据

select * from table_name

检索表中的数据并最多显示5行

select * from table_name limit 5

去重

select distinct 字段 from table_name

排序

select * from table_name order by 字段

分组

select * from table_name group by 字段

判断条件

select * from table_name where xxxxxx

自联结

select p1.scores,p1.id from scores as p1 ，scores as p2 where p1.stu_id = p2.stu_id and p2.id = 2;

左外联结

select students.name,scores.score from students left outer join scores on students.stu_id = scores.stu_id and scores.score < 60;

内联结

select students.name,scores.score from students inner join scores on students.stu_id = scores.stu_id and scores.score < 60; 内联结

子查询

select name from students where stu_id in (select stu_id from scores where score < 60);

视图

reate or replace view 视图名 as

查看索引

show index from table_name

创建索引

create index name_index on table_name

删除索引

drop index name_index on table_name