Mysql select語句設置默認值

1.在沒有設置默認值的情況下：

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

結果：

設置顯示默認值：

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：假設region_name一列的值為空，則顯示為0，結果為：

本文為Eliot原創。轉載請注明出處：http://blog.csdn.net/xyw_blog/article/details/26250331