1 inner join
满足条件则展示,否则不展示
2 left join
左表为主:左表有则展示,右表字段无则补null
3 right join
右表为主:右表有则展示,左表字段无则补null
posted on 2022-07-28 11:56 爱老虎哟 阅读(49) 评论(0) 编辑 收藏 举报
Powered by: 博客园 Copyright © 2024 爱老虎哟 Powered by .NET 8.0 on Kubernetes