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Mysqlselect语句设置默认值的方法_MySQL

时间:2021-07-01 10:21:17 帮助过:7人阅读

1.在没有设置默认值的情况下:


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:


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

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