操作数据库:
1.创造数据库:Create database database_name;
2.删除数据库:Drop database database_name;
3.创建新表：create table tabel_name(col1 type1 [not null] [primary key], col2 ...);
以旧表创建新表:create table table_name_new like tab_old
create table table_new as select col1,col2,..from tab_old definition only;
4.删除表：drop table table_name;
5.增加列:alter table table_name add column colname typename
删除列 alter table table_name drop column coluname
6.添加主键:alter table table_name add primary key (colName)
删除主键：alter table table_name drop primary key(colName)
7.创建索引:create [unique]index indexName on tableName(col...)
删除索引：drop index indexName on tableName
8.创建视图:create view viewname as select_statement
删除视图:drop view viewName
9.常用语句: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%’ 排序：select * from table1 order by field1,field2 [desc]
总数：select count(field) 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
