Looping a query from previous result in mysql - php

Question

I have two tables, user and leads. My goal is to find users with leads having status 'completed' and 'idle', after that use that result to get all the leads for that user. Here is my query
$sql = "SELECT u.id FROM users u LEFT JOIN leads l ON u.id = l.user_id WHERE l.status IN('completed', 'idle')";
...
$result = $stmt->fetchAll();
...
$usersleads = array();
foreach ($result as $userId) {
$sql = "SELECT * FROM leads where user_id = ". $userId;
...
$results = $stmt->fetchAll();
foreach ($results as $ul) {
array_push($usersleads, $row);
}
}
This works for small results. But if data gets bigger this just crashed and I can understand it. I am looking for a more efficient way to query the db.
UPDATE
I think I have found a solution. Now only has two queries over all.
$sql = "SELECT u.id FROM users u LEFT JOIN leads l ON u.id = l.user_id WHERE l.status IN('completed', 'idle')";
...
$userResult = $stmt->fetchAll();
...
$userIds = [];
foreach ($userResult as $user) {
$userIds[] = $user['id'];
}
$sql = "SELECT * FROM leads where user_id IN('" . implode("','", $userIds) ."')";
...
$leadsResult = $stmt->fetchAll();
...
foreach ($userResult as &$lead) {
$lead['date'] = $this->getDateForLead($lead['id'], $leadsResult);
// add other fields to $userResult
}
...
public function getDateForLead($leadId, $leads)
{
foreach($leads as $lead) {
if ($leadId = $lead['id']) {
return $lead['date'];
}
}
return null;
}