ActiveRecord 查询 (PostgreSQL) 中的日期时间算法 [英] DateTime arithmetic in an ActiveRecord query (PostgreSQL)

问题描述

我在 User/users 表中有两个 datetime 列:created_at 和 birthdate.我想查找出生日期在其创建日期之前不到 13 年的用户.

I have two datetime columns in a User/users table: created_at and birthdate. I'd like to find users whose birthdate is less than 13 years before their creation date.

等效的 Rails if 语句将是 ((created_at -birthdate) <13.years)

The equivalent Rails if statement would be ((created_at - birthdate) < 13.years)

如何将其转换为 ActiveRecord 查询(可在 PostgreSQL 上使用的查询)?这甚至可能吗，还是我必须手动遍历所有记录?

How do I translate this to an ActiveRecord query (one that'll work on PostgreSQL)? Is this even possible, or will I have to iterate over all records manually?

推荐答案

最简单的方法是使用 间隔，那么它几乎是 Rails 版本的直接音译:

The easiest way to do this is to use an interval, then it is pretty much a straight transliteration of the Rails version:

User.where(%q{created_at - birthdate < interval '13 years'})

两个时间戳(或时间戳和日期)之间的差异是一个间隔，因此您只需要比较右侧的适当值即可.

The difference between two timestamps (or a timestamp and a date) is an interval so you just need the appropriate value on the right side of your comparison.

这篇关于ActiveRecord 查询 (PostgreSQL) 中的日期时间算法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！