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MySQL-数据操作-增删改查

1.增加:

insert into 表 (列名,列名...) values (值,值,值...)
insert into 表 (列名,列名...) values (值,值,值...),(值,值,值...)
insert into 表 (列名,列名...) select (列名,列名...) from

2.删除:

delete fromdelete fromwhere id=1 and name=alex

3.修改:

updateset name = alex where id>1

4.查询:

select * fromselect * fromwhere id > 1
select nid,name,gender as gg fromwhere id > 1

5.补充

a、条件
    select * fromwhere id > 1 and name != alex and num = 12;
 
    select * fromwhere id between 5 and 16;
 
    select * fromwhere id in (11,22,33)
    select * fromwhere id not in (11,22,33)
    select * fromwhere id in (select nid from 表)
 
b、通配符
    select * fromwhere name like ale%  - ale开头的所有(多个字符串)
    select * fromwhere name like ale_  - ale开头的所有(一个字符)
 
c、限制
    select * from 表 limit 5;            - 前5行
    select * from 表 limit 4,5;          - 从第4行开始的5行
    select * from 表 limit 5 offset 4    - 从第4行开始的5行
 
d、排序
    select * fromorder byasc              - 根据 “列” 从小到大排列
    select * fromorder bydesc             - 根据 “列” 从大到小排列
    select * fromorder by 列1 desc,列2 asc    - 根据 “列1” 从大到小排列,如果相同则按列2从小到大排序
 
e、分组
    select num fromgroup by num
    select num,nid fromgroup by num,nid
    select num,nid fromwhere nid > 10 group by num,nid order nid desc
    select num,nid,count(*),sum(score),max(score),min(score) fromgroup by num,nid
 
    select num fromgroup by num having max(id) > 10
 
    特别的:group by 必须在where之后,order by之前
 
f、连表
    无对应关系则不显示
    select A.num, A.name, B.name
    from A,B
    Where A.nid = B.nid
 
    无对应关系则不显示
    select A.num, A.name, B.name
    from A inner join B
    on A.nid = B.nid
 
    A表所有显示,如果B中无对应关系,则值为null
    select A.num, A.name, B.name
    from A left join B
    on A.nid = B.nid
 
    B表所有显示,如果B中无对应关系,则值为null
    select A.num, A.name, B.name
    from A right join B
    on A.nid = B.nid
 
g、组合
    组合,自动处理重合
    select nickname
    from A
    union
    select name
    from B
 
    组合,不处理重合
    select nickname
    from A
    union all
    select name
    from B

 

MySQL-数据操作-增删改查