MySQL使用字符串作为查询条件
前言:今天在做MySQL的查询时遇到一个问题,情景是这样的,假如现在我的一张表里面有一个字段scode(表示商品编号),然后有一个
前言:今天在做MySQL的查询时遇到一个问题,情景是这样的,假如现在我的一张表里面有一个字段scode(表示商品编号),然后有一个字符串存储了多个商品编号,如“0001ME,0002BL”是一个字符串,假如叫str,本来是打算使用in的方式,就是说想把str作为in的条件,如下where scode in “0001ME,0002BL”,但是没有成功,然后就查阅MySQL的文档,找各种函数,最后发现了instr这个函数,问题解决了,下面说一下结果过程
1.开始的时候一直在将字符串str转换为类似的in参数,如下
SELECT * FROM stocks_orderlist s where s.scode in ("0001ME","0002BL") LIMIT 10;
SELECT CONVERT(CONCAT("\'",REPLACE("0001ME,0002BL","\,","\'\,\'"),"\'"),CHAR);
SELECT * FROM stocks_orderlist s where s.scode in (CONVERT(CONCAT("\"",REPLACE("0001ME,0002BL","\,","\"\,\""),"\""),CHAR)) LIMIT 10;
虽然把str转成了in所要的东西,但是后来想想,in的参数是一个列表集合,我及时把str转换成了所谓的in参数的形式,,但是肯定还是一个字符串,于是又忙碌了半天,有点想放弃的感觉,但是回头想想,肯定是自己没有找到合适的办法,于是就找到了instr函数
2.instr函数,看帮助文档的意思是找出substr在str中第一次出现问题,尝试如下
SELECT INSTR("0001ME,0002BL","0003ME");
SELECT INSTR("0001ME,0002BL","0001ME");
SELECT INSTR("0001ME,0002BL","0002BL");
SELECT * FROM stocks_orderlist s where INSTR("0001ME,0002BL",s.scode);
总结:看起来很小的一个方法,假如不知道方法的时候却很痛苦啊。
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Ubuntu 14.04下安装MySQL
《MySQL权威指南(原书第2版)》清晰中文扫描版 PDF
Ubuntu 14.04 LTS 安装 LNMP Nginx\PHP5 (PHP-FPM)\MySQL
Ubuntu 14.04下搭建MySQL主从服务器
Ubuntu 12.04 LTS 构建高可用分布式 MySQL 集群
Ubuntu 12.04下源代码安装MySQL5.6以及Python-MySQLdb
MySQL-5.5.38通用二进制安装
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