一、常用的sql语句
1、建表语句
create table tabname(colname1 type1 [not null][primary key], colname2 type2,...)
根据已有的表创建新表
A：create table tab_new like tab_old
B:create table tab_new asselect colname1,colname2... from tab_old definition only
2、删除表
drop table tabname
3、增加一列
alter table tabname add column type DEFAULT '' COMMENT '***'
4、常用的基本的sql
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 orderby field1,field2 [desc]
总数：select countas 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
二、提升
1、replace
select replace(object,'old_text','new_text')
update table set name=replace(name,'aa',bb') where name like '%查找的内容%'