定义:sql 语句就是对数据库进行操作的一种语言。
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%’ (所有包含‘value1’这个模式的字符串)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[separator]