Rails activerecord get user with id dividable by 3

Question

How to get user who has an ID dividable by 3

something like :

User.where(id: id % 3 == 0)

thanks

Answer 1

You can use pure string condition here, because data is static (not coming from user for example):

User.where('id % 3 = 0')

Read more in official docs.

Answer 2

If the database is Oracle, then you can do the following:

User.where('mod(id, 3) = 0')

Query:

2.1.2-perf :004 > User.where('mod(id, 3) = 0').to_sql
 => "SELECT \"users\".* FROM \"users\"  WHERE (mod(id, 3) = 0)"

Sql fiddle demo for this query here.