mysql 基本语句

mysql sql语句大全


1、创建数据库语句

CREATE DATABASE dbname(数据库名字)


2、删除数据库语句

drop database dbname


3、创建新表语句

create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)


4、根据已有的表创建新表语句:

create table tab_new as select col1,col2… from tab_old


5、删除新表语句

drop table tabname(表名)

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6、增加一个列语句

Alter table tabname add column col type


7、添加主键语句: Alter table tabname add primary key(col)

Alter table tabname drop primary key(col)


8、创建索引语句:create [unique] index idxname on tabname(col….)

删除索引:drop index idxname

注:索引是不可更改的,想更改必须删除重新建。


9、创建视图语句:create view viewname as select statement

删除视图:drop view viewname


10、几个简单的基本的sql语句

选择:select * from table1 where 范围

插入:insert into table1(field1,field2) values(value1,value2)

删除:delete from table1 where 范围

更新:update table1 set field1=value1 where 范围

查找:select * from table1 where field1 like ’%value1%’ ---like的语法很精妙,查资料!

排序:select * from table1 order by field1,field2 [desc]

总数:select count as totalcount from table1

求和:select sum(field1) as sumvalue from table1

平均:select avg(field1) as avgvalue from table1

最大:select max(field1) as maxvalue from table1

最小:select min(field1) as minvalue from table1


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