基本SQL语句。
创建数据库
CREATE DATABASE database-name
删除数据库
DROP database dbname
创建新表
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)根据已有的表创建新表
create table a as select * from b(使用旧表创建新表)
删除新表
DROP table tabname
添加字段的语法：
alter table tablename add (column datatype [default value][null/not null],….);修改字段的语法：
alter table tablename modify (column datatype [default value][null/not null],….);删除字段的语法：
alter table tablename drop (column);
几个简单的基本的sql语句
插入：
1. insert into table1(field1,field2) values(value1,value2)
2. insert into table1(table1.field1,table1.field2)select table2.field3 field1,table2.field4 field2 from table2 where 范围
删除：delete from table1 where 范围
更新：
1. update table1 set field1=value1 where 范围
2. update table1 set (table1 .field1)=(select table12.field1 from table2 where 范围) 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 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