In a cakephp 3 app, how do I build a query that finds all from a Table that does NOT contain it's associated table?
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21-12-2019 - |
Question
Is there a simple way to get the inverse of the contain
method of the querybuilder?
I'm using belongsToMany associations with a join table to associate the two Models.
EmailsTable $this->belongsToMany('Issues');
IssuesTable $this->belongsToMany('Emails');
so I can't just do something like:
$unparsed_emails = $this->Emails->find('all')->where(['issue_id is null']);
It seems like the inverse of the following would provide Emails that do NOT have associated Issues yet:
$unparsed_emails = $this->Emails->find->contain(['Issues']); //need inverse of this
I think I must be missing something from the cakephp 3 ORM/Querybuilder documentation, but I can't find it.
Solution
I'm not yet that much into the query builder, so I'm not sure whether there are simpler methods, but a left join should do it.
$this->Emails
->find('all')
->leftJoin('emails_issues', 'emails_issues.email_id = Emails.id')
->where('emails_issues.id IS NULL');
This should translate into a query like
SELECT
Emails.id AS `Emails__id`, ...
FROM
emails AS Emails
LEFT JOIN
emails_issues emails_issues ON emails_issues.email_id = Emails.id
WHERE
emails_issues.id IS NULL
which would select all emails that don't have any issues assigned.