常见SQL语句

CREATE DATABASE 你要创建的数据库名字 

drop database 你要删的数据库名字

create table 你要创建的表的名字(属性名称1 数据类型1  [not null] [设置主键],
                                             属性名称2 数据类型2  [not null],
                                               ..)        

Alter table tabname drop primary key(属性名称)

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