mysql高级操作(优化)

     /*
         Mysql基础操作(优化)
         @auther: luowen
         @time: 2013-07-26

     1.mysql复制表机构和表数据
         create table t1 like t2; 
         insert into t1 select * from t2;
     2.mysql创建索引
         method 1:
             increate [unique] [index] [primary key] indexName on t1(name);
             show index from t1;
             drop index [unique] [index] [primary key]indexName on t1;    
        method 2:
            alter table t1 add [index][unique][primary key] indexName (column);
            alter table t1 drop [index][unique][primary key] indexName;
     3.mysql 视图
         create view v_t1 as select * from t1 where id >　3;
         drop view v_t1;
     4.mysql 内置函数
         [字符串函数]
             1.连接函数
                 concat select concat('luowe','wen') as luowen;
             2.大小写转换
                 lcase select lcase('SDFSADF') as demo
                 ucase select ucase('asdfsadf') as demo2
             3.长度 length
                 length select length('sdfsadfsadf');
             4.去空
                 ltrim select ltrim('           sadfsdf')
                 rtrim select rtrim('asdfsaf       ')
             5.重复
                 repleat select repleat('xx',10)
             6.替代
                 replace select replace('linux is very good','linux','php') ;
             7.截取
                 substr select substr('linux is very good',pos,length);   // pos 是从1开始
             8.生成空格
                 space select space(10); select concat(space(10),'linux'); //在linux左侧添加了10个空格
         [数学函数]
             1.二进制函数
                 bin select bin(10);
             2.取整
                 ceiling select ceiling(2.5)     //3
                 floor select floor(2.5) //2
             3.最大最小
                 max max(col);    //聚合使用
                 min min(col);
             4.平方根
                 sqrt select sqrt(2);
             5.随机数
                 rand select rand(count); //count 选出几个 配合order by 可是实现随机排序
         [日期函数]
             1.curdate //当前时间
             2.curtime
             3.now();
             4.unix_timestamp
             5.week
             6.year
             7.datediff('日期1','日期2') //计算中间差了几天


    5: mysql 的预处理
        prepare preTable from "select * from t2 where id > ?";

        set @i=3;

        execute preTable using @i; //@i替代了prepare 语句中的?号

        drop prepare preTable //删除预处理
    6:mysql 事务(MyISAM不支持事务,innoDB支持)
        set autocommit = 0; //打开事务
        //alter table t2 engine innodb;//修改表引擎
        delete from t2 where id < 1;
        savepoint p1
        delect form t2 where id < 3;
        savepoint p2;

        rollback to p2 //还原到p2的点

        rollback    //回滚
        commit         //提交
    7:mysql 存储
        procedure   //一个小段的程序
        d //       //将存储设置定界符
        create procedure p1()
            begin
                set @i = 3
                    while @i <= 100 do
                    insert into t2(name) values(concat('user',@i));
                    end while;
            end//
        show create procedure p2   //查看存储
        call p2   //呼叫执行p2
        drop prcedure p2
    8:mysql 触发器
        trigger
            d //      //修改定界符
            create trigger tg1 before insert on t1 for each row
                begin
                    insert into t2(id) value(new.id);
                end
    9:auto_increment 恢复1
        truncate table; //已经恢复1
        delete from table //没有恢复
        alter table auto_increment = 1;



    [mysql regex]

        1.select name,email from table where email regexp '@163[.,]com$'
        select name ,email from table from email like '%@163.com' or email like '%@163.com';

    [sql optimize]
        1.SQL优化步骤
            MyISAM ENGINE
                show status like 'Com_%'; //查看mysql curd 操作次数
                show global status like 'Com_%';//查看服务器启动至今
            INNODB ENGINE
                show status like "innodb_rows"; //查看innodb引擎的记录

            show Status like "slow_querys";//查看慢查询

        [mysql 数据导入导出]
            mysqldump -uroot -pluowen test > /home/test.sql
        select * from table2 in outfile '/home/table2.sql';
        load data infile "/home/table2.sql" into table2 t1;

        alter table tableName disable keys//导入数据的时候,先关闭索引,就可以一起插入数据后最后加索引
        loading the data
        alter table tableName enable keys//最后打开所以

        set unique_checks=0//关闭唯一索引
        set unique_checks=1//恢复唯一索引