SQL on 老冯云数https://vonng.com/tags/sql/Recent content in SQL on 老冯云数Hugo -- gohugo.iozh-cnrh@vonng.com (冯若航)rh@vonng.com (冯若航)© 2025 冯若航Fri, 06 Apr 2018 00:00:00 +0000Distinct On 去除重复数据https://vonng.com/pg/sql-distinct-on/Fri, 06 Apr 2018 00:00:00 +0000rh@vonng.com (冯若航)https://vonng.com/pg/sql-distinct-on/使用Distinct On扩展字句快速找出分组内具有最大最小值的记录。用 Exclude 实现互斥约束https://vonng.com/pg/sql-exclude/Fri, 06 Apr 2018 00:00:00 +0000rh@vonng.com (冯若航)https://vonng.com/pg/sql-exclude/Exclude约束是一个PostgreSQL扩展，它可以实现一些更高级，更巧妙的的数据库约束。