首页 / PHP / sql，去重查询distinct
sql，去重查询distinct
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了sql，去重查询distinct，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含1846字，纯文字阅读大概需要3分钟。
内容图文
select DISTINCT `object_id`, t3.width as width, t3.height as height,t3.ismark as ismark, t2.rtime as add_time,t1.add_author as add_author,t1.image_url as image_url,t1.id as id,t1.browse_real_cnt as browse_real_cnt from comments as t2 left join ornamentations as t1 on t1.id = t2.object_id left join ornamentation_images as t3 on t3.ornamentation_id = t1.id where ( t2.uid = 1013 ) AND ( t1.enable = '0' ) ORDER BY t2.id desc LIMIT 0,5
select后面的条件，带t3正常，能去重复的，加了t2，t1就没法去重复的了
回复讨论(解决方案)
DISTINCT 作用于整行
你的3个表中只要存在一对多的情况就难说了
DISTINCT 作用于整行
你的3个表中只要存在一对多的情况就难说了
那该怎么写呢?我刚才也查了，一个表用distinct，多个表的时候就不用它了，我没看懂别人的说法
再套一个 select
select DISTINCT * from (`object_id`, t3.width as width, t3.height as height,t3.ismark as ismark, t2.rtime as add_time,t1.add_author as add_author,t1.image_url as image_url,t1.id as id,t1.browse_real_cnt as browse_real_cnt from comments as t2 left join ornamentations as t1 on t1.id = t2.object_id left join ornamentation_images as t3 on t3.ornamentation_id = t1.id where ( t2.uid = 1013 ) AND ( t1.enable = '0' ) ORDER BY t2.id desc) T LIMIT 0,5
再套一个 select
select DISTINCT * from (`object_id`, t3.width as width, t3.height as height,t3.ismark as ismark, t2.rtime as add_time,t1.add_author as add_author,t1.image_url as image_url,t1.id as id,t1.browse_real_cnt as browse_real_cnt from comments as t2 left join ornamentations as t1 on t1.id = t2.object_id left join ornamentation_images as t3 on t3.ornamentation_id = t1.id where ( t2.uid = 1013 ) AND ( t1.enable = '0' ) ORDER BY t2.id desc) T LIMIT 0,5
报错，报
from comments as t2
from错了
哦，漏了 select
..... from
( select `object_id`, t3.width as....
内容总结
以上是互联网集市为您收集整理的sql，去重查询distinct全部内容，希望文章能够帮你解决sql，去重查询distinct所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。