Check if a value exists in a database and return the value if it does Rails

Question

I am running Rails here with a User model that contains an :email_address column

I have an array - emails_to_check[email1,email2,email3] that i want to check if they exist in the User database.

I only want to return the values that DO exist in the database

Answer 1

Here's a simple one-liner for you. There may be more performant ways, but this is maybe the most straight-forward and idiomatic Rails.

emails_to_check = ['email1', 'email2', 'email3']
User.where(email_address: emails_to_check).pluck(:email_address)

Here is the resulting SQL query:

SELECT `users`.`email_address` FROM `users` WHERE `users`.`email_address` IN ('email1', 'email2', 'email3');