如何在 Laravel 数据库查询生成器中使用 CASE WHEN IN

Question

I have users table and a followers table. I'm doing a search to get all the users with a specific keyword, but I want the ones which are followers of the current user to appear first. I can get all the followers id's in a subquery, so my idea was to do something like this:

SELECT id, name, surname, 
CASE WHEN id IN (SELECT followable_id FROM followers WHERE followable_id = $currentUserId --this is a variable)  THEN 1
ELSE 0
END AS friend
FROM users
ORDER BY friend
WHERE name = 'keyword';

I've been trying to get this in my Laravel controller, but I can't find the way. How could I use this SQL select in my Laravel controller? How could translate this SQL code to the Laravel Database Query Builder ?

What I have already tried:

Following @aynber answer, I wrote the following code:

$orderedMachingUsers = DB::table('users')
    ->whereIn('id', $matchingUsersId)->select(
        [
            '*', 
            DB::raw('CASE WHEN id IN ? THEN 1 ELSE 0 END AS friend', [$friendsId])]
    )
    ->orderByRaw('friend')
    ->get();

It seems close, but I'm still geting a "SQLSTATE[42000]: Syntax error or access violation: 1064" error.

Answer 1

You need to pass the case statement in with a raw clause

DB::table('users')
    ->where('name', 'keyword')->select(
        [
            'id', 
            'name', 
            'surname', 
            DB::raw('CASE WHEN id IN (SELECT followable_id FROM followers WHERE followable_id = ?) THEN 1 ELSE 0 END AS friend', [$curentUserId])]
    )
    ->orderByRaw('friend')
    ->get();

Answer 2

the syntax for in condition should be like CASE WHEN id IN (?,?,?) THEN so you need to add ? with the count of $friendsId

so you should use the following

$placeholders = str_repeat ('?,',  count($friendsId) - 1) . '?';
$orderedMachingUsers = DB::table('users')
    ->whereIn('id', $matchingUsersId)->select(
        [
            '*', 
            DB::raw('CASE WHEN id IN ('. $placeholders .') THEN 1 ELSE 0 END AS friend', [$friendsId])]
    )
    ->orderByRaw('friend')
    ->get();