Mysql select语句设置默认值的方法

2978 2014-5-31 01:01

1.在没有设置默认值的情况下:

复制代码 代码如下:

SELECT userinfo.id, user_name, role, adm_regionid, region_name , create_time
FROM userinfo
LEFT JOIN region ON userinfo.adm_regionid = region.id


结果:



设置显示默认值:

复制代码 代码如下:

SELECT userinfo.id, user_name, role, adm_regionid, IFNULL(region_name,0) as region_name, create_time
FROM userinfo
LEFT JOIN region ON userinfo.adm_regionid = region.id


即:如果region_name一列的值为空,则显示为0,结果为:



本文来自:http://blog.csdn.net/xyw_blog/article/details/26250331