Mysql SELECT statement method to set default values _mysql

1. Without setting a default value:

Copy Code code as follows:

SELECT userinfo.id, user_name, role, Adm_regionid, Region_name, Create_time
From UserInfo
Left JOIN region on userinfo.adm_regionid = Region.id

Results:

To set the default value for display:

Copy Code code as follows:

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

That is, if the value of the Region_name column is empty, it is displayed as 0, and the result is:



This article is from: http://blog.csdn.net/xyw_blog/article/details/26250331