使用case和when语句加入laravel

Question

我在Mysql中跟踪查询：

SELECT 
U.* FROM
`cr_friends` AS `cf`  JOIN
`users` AS `U` WHERE
    `cf`.`status` = 1
    AND 
    (
        CASE
            WHEN `cf`.`friend_to` = 1 THEN `cf`.`friend_from` = `U`.`id`
            WHEN `cf`.`friend_from` = 1 THEN `cf`.`friend_to` = `U`.`id`
        END
    ) GROUP BY `U`.`id` ORDER BY `cf`.`created` desc;

我试图通过以下方式将此放入laravel中：

$myFriendsData = DB::table('cr_friends as cf')
        ->where('cf.status', '=', 1)
        ->Join('users as U')
        ->select(
            DB::raw(
                '(
                    CASE WHEN cf.friend_to = ' . auth()->user()->id . ' THEN cf.friend_from = U.id  END
                    CASE WHEN cf.friend_from = ' . auth()->user()->id . ' THEN cf.friend_to = U.id  END
                )'
            )
        )
        ->select('U.*')
        ->orderBy('U.id', 'desc')
        ->get();

但没有成功，因为mysql查询工作正常，但是此laravel查询不会。

实际上，我认为，Join存在问题，我将其放入laravel中，它要求再输入一个参数，但是在这种情况下，我无法做到这一点。

你们能指导我，以便我实现这一目标吗？

谢谢兰德

Answer 1

为join()提供一个空的闭包，并使用whereRaw() ：

$myFriendsData = DB::table('cr_friends as cf')
    ->where('cf.status', '=', 1)
    ->join('users as U', function() {})
    ->whereRaw(
        '(
            CASE 
                 WHEN cf.friend_to = ' . auth()->user()->id . ' THEN cf.friend_from = U.id
                 WHEN cf.friend_from = ' . auth()->user()->id . ' THEN cf.friend_to = U.id  
            END
        )'
    )
    ->select('U.*')
    ->orderBy('U.id', 'desc')
    ->get();

Answer 2

用这个

$myFriendsData = DB::table('cr_friends as cf')
    ->Join('users as U')
    ->where('cf.status', '=', 1)
    ->where(
        DB::raw(
            '(
                CASE WHEN cf.friend_to = ' . auth()->user()->id . ' THEN cf.friend_from = U.id  END
                CASE WHEN cf.friend_from = ' . auth()->user()->id . ' THEN cf.friend_to = U.id  END
            )'
        )
    )
    ->select('U.*')
    ->orderBy('U.id', 'desc')
    ->get();

Answer 3

我在Laravel 5.8版的join中使用了DB::raw作为case end语句

DB::table('users')
    ->join('settings', function ($join) {
        $join->on('settings.id', '=', DB::raw(case when users.type = "admin" then users.admin_setting_id else users.setting_id end'));
    })
    ->get();