在 Rails 中搜索表连接

Question

Suppose I have two tables, one called zombies (id, name, graveyard), and one called weapons (id, name, strength, zombie_id). Weapons:belongs_to Zombies What's the easiest way to find the weapon that has a zombie of name 'jack'?

Thanks!

Answer 1

Weapon.includes(:zombie).where("zombies.name = ?", "jack")

This will return a collection, so if you want just the first, append .first to that query.

So in conclusion: includes will do a join, but also keep around the table included so you can reference it in the where clause.