Using subqueries in Eloquent/Laravel

Question

Here's the query in raw SQL:

SELECT * 
FROM (
    SELECT `characters`.`id`,`characters`.`refreshToken`,
           `characters`.`name`,max(`balances`.`created_at`) as `refreshDate`
        FROM `characters`
        INNER JOIN `balances` ON `characters`.`id` = `balances`.`character`
        WHERE `characters`.`refreshToken` IS NOT NULL
        GROUP BY `characters`.`id`
) AS `t1`
WHERE `refreshDate` < '2017-03-29';

I've tested this in phpMyAdmin and it returns the expected results. However I'm using the Eloquent and Laravel libraries in my PHP app and I'm not sure how to approach this. How exactly do subqueries work in this case?

Answer 1

You can do a subquery as a table but need to create the subquery first and then merge the bindings into the parent query:

$sub = Character::select('id', 'refreshToken', 'name')
    ->selectSub('MAX(`balances`.`created_at`)', 'refreshDate')
    ->join('balances', 'characters.id', '=', 'balances.character')
    ->whereNotNull('characters.refreshToken')
    ->groupBy('characters.id');

DB::table(DB::raw("($sub->toSql()) as t1"))
    ->mergeBindings($sub)
    ->where('refreshDate', '<', '2017-03-29')
    ->get();

If that is your entire query you can do it without the subquery and use having() instead like:

Character::select('id', 'refreshToken', 'name')
    ->selectSub('MAX(`balances`.`created_at`)', 'refreshDate')
    ->join('balances', 'characters.id', '=', 'balances.character')
    ->whereNotNull('characters.refreshToken')        
    ->groupBy('characters.id')
    ->having('refreshDate', '<', '2017-03-29');