Return SQL subquery as boolean field?

Question

I would like to do something like this (mix of sql with pseudocode):

let's assume for this example that there is a separate phone number table:

person: person_id, person_name, person_lastName
phone_number: phonenmb_id, phonenmb_number, phonenmb_person_id

SELECT p.name, p.lastName, hasPhoneNumber = hasPhoneNumber(someNumber)

In the example i would like to get some data from a person, and given a certain phone number, return TRUE if the person has that number on it's number list, or FALSE if it doesn't.

If anyone can provide a hint on how to do this directly with Doctrine and DQL it'd be awesome, otherwise i'll just translate it to DQL myself.

Answer 1

One approach is to outer join to the phone number table using the person_id and the phone number, and then check if the outer join was satisfied to calculate the boolean.

Example using your schema:

SELECT p.person_name, p.person_lastName, 
  (pn.phonenmb_id IS NOT NULL) as hasPhoneNumber
FROM person p
  LEFT OUTER JOIN phone_number pn on pn.phonenmb_person_id = p.person_id 
                                 and pn.phonenmb_number = someNumber
GROUP BY p.person_name, p.person_lastName