mysql>select*fromtest;+----+----------+-------+-----------+|id|name|score|subject|+----+----------+-------+-----------+|1|xiaoming|89|shuxue||2|xiaohon...

 mysql>select*fromtest;+----+----------+-------+-----------+|id|name|score|subject|+----+----------+-------+-----------+|1|xiaoming|89|shuxue||2|xiaohon...

 mysql>select*fromtest;+----+----------+-------+-----------+|id|name|score|subject|+----+----------+-------+-----------+|1|xiaoming|89|shuxue||2|xiaohon...

 mysql>select*fromtest;+----+----------+-------+-----------+|id|name|score|subject|+----+----------+-------+-----------+|1|xiaoming|89|shuxue||2|xiaohon...

 mysql>select*fromtest;+----+----------+-------+-----------+|id|name|score|subject|+----+----------+-------+-----------+|1|xiaoming|89|shuxue||2|xiaohon...

 mysql>select*fromtest;+----+----------+-------+-----------+|id|name|score|subject|+----+----------+-------+-----------+|1|xiaoming|89|shuxue||2|xiaohon...

 mysql>select*fromtest;+----+----------+-------+-----------+|id|name|score|subject|+----+----------+-------+-----------+|1|xiaoming|89|shuxue||2|xiaohon...

%匹配任意长度_匹配单个字符mysql>select*fromtable1;+----------+------------+-----+---------------------+-------+|name_new|transactor|pid|order_date|price|+----------+----...

 mysql>select*fromtable1;+----------+------------+-----+---------------------+-------+|name_new|transactor|pid|order_date|price|+----------+------------...

//添加一个字段pid并且设置为主键（auto_increment）自增（auto_increment），不可为null,类型为intunsignedaltertabletable1addpidintunsignednotnullauto_incrementprimarykey;//可以将一个主键修改为0updatet...

唯一键特点：1、唯一键在一张表中可以有多个。2、唯一键允许字段数据为NULL，NULL可以有多个（NULL不参与比较）//一个表中允许存在多个唯一键,唯一键允许为空,在不为空的情况下,不允许重复//设置一个字段为唯一键mysql>altertable`table1`addunique(`name_new`);Qu...

 //不允许为nullaltertabletable1changeididint(10)notnull;//允许为nullaltertabletable1changeididint(10)null; //name_new允许为空inserttable1(id,transactor)values(1,...

 mysql>altertabletable1addpriceint(10)notnull;QueryOK,0rowsaffected(0.05sec)Records:0Duplicates:0Warnings:0//删除一个字段ALTERTABLEtable1dropid;  ...

 //修改字段长度altertabletable1modifynamechar(15);//修改字段名称以及长度altertabletable1changenamename_newchar(32);altertabletable1changeididint(10); ...

 //重命名表renametabletable1totable2;//重命名多个表renametabletable1totable2,table3totable4,table5totable6; ...