How to query a confirmation-type custom user field?

Support
6

This is because a row is only added to the user_custom_fields table after a user has changed the value. So what you want to do is

  • Go through the users table
  • For each user, see if there’s a user_custom_fields row for user_field_5
  • If so, check whether it’s true, otherwise assume it’s false

In my testing, ticking a boolean saves as true in the database, while unticking saves as NULL

So I think the SQL you want is

SELECT u.id as user_id, cf.value
FROM users u
LEFT JOIN user_custom_fields cf 
ON (cf.user_id = u.id and cf.name like 'user_field_5')
WHERE cf.value IS DISTINCT FROM 'true'

Note that IS DISTINCT FROM is needed rather than !=, because it can deal with one of the values being NULL.