/**
* Add a condition over a related model.
*
* Usage:
* ------
*
* There is different calling form for this function.
*
* * Check existence of related models. This is a merely a WHERE EXISTS
* clause in SQL:
*
* `$query->root('Blog')->has('articles');`
*
* * Perform a condition over the *number* of related models:
*
* `$query->root('Blog')->where('articles', '>', 100);`
*
* This would retrieve blogs instance which contains at least one hundred
* articles.
*
* * Use a Closure to add conditions to the subquery:
*
* ```php
* $query->root('Blog')->has('articles', function ($q) {
* $q->where('online', true);
* });
*
* @param string $relation The name of the relation to check on.
* @param string $op Optional. The operator for the second use form.
* @param mixed $value Optional. The value for the second use form.
*
* @return $this
*/
public function whereHas($relation, $op = null, $value = null, $not = false)
{
$mainQuery = $this->getQueryOrNewSelect();
$mainQueryRootAlias = $mainQuery->getBuilder()->getRootAlias();
// We'll use $rels for recursivity.
$rels = explode('/', $relation);
$relation = array_shift($rels);
$root = $this->getRoot();
$rel = $root::relation($relation);
// We construct the sub-query. It can be the sub-query of an Exists
// clause or a Count (if $op and $value are given).
$subRootAlias = $this->getRootAlias();
$subRootAlias = $subRootAlias ? $subRootAlias . '.' . $rel->name : $rel->name;
$subQuery = new self($rel->lm->class, $subRootAlias);
$subQuery->setConnection($this->getConnection());
$subQuery->newSelect();
$subQuery->whereRelation($rel, $mainQueryRootAlias);
$subQuery->getQuery()->getCompiler()->useTableAlias = true;
$mainQuery->getQuery()->getCompiler()->useTableAlias = true;
if ($rels) {
$relation = implode('/', $rels);
$subQuery->whereHas($relation);
}
// We want a Count sub-query.
if ($op !== null && $value !== null) {
$subQuery->getQuery()->addAggregate('COUNT');
$mainQuery->selectSub($subQuery->getQuery(), '#' . $relation);
$mainQuery->where(DB::expr('#' . $relation), $op, $value, null, $not);
} else {
if ($op instanceof \Closure) {
$op($subQuery);
}
$subQuery->get(array('*'), false);
$mainQuery->whereExists($subQuery->getQuery(), null, $not);
}
return $this;
}