Rails - Delete all Records that Meet a Condition

Try this:

Manager.delete_all(manager_level: 5)

I think it is better to use destroy instead of delete

because destroy will delete current object record from db and also its associated children record from db (https://stackoverflow.com/a/22757656/5452072)

Also delete will skip callbacks, but destroy doesn't.

Manager.where(:manager_level => 5).destroy_all