选择不在另一个表中的所有列laravel 5.5

问题描述：

我有两个表-第一个表称为用户"，第二个表称为"buy_courses".

I have two tables - the first one is called 'users' and the second one is called 'buy_courses'.

我正在尝试选择所有用户名不在buy_courses中的用户.我尝试过-

I am trying to select all users those user_name is not in buy_courses. I tried something like -

$users = DB::table('users')
                ->rightjoin('buy_courses', 'users.user_name', '=', 'buy_courses.user_name')
                ->get();

当我使用'<>'时，它将返回其user_name位于'buy_courses'中的所有用户，那么我将获得所有用户.什么是正确的查询?

It returns all users, whose user_name is in 'buy_courses', when I am using '<>', then I'm getting all users. What should be the right query?

答

DB::table("users")->select('*')->whereNotIn('user_name',function($query) {

   $query->select('user_name')->from('buy_courses');

})->get();

只是 join 实际上是Laravel中的内部联接，因此也许您也可以尝试:

just join actually is inner join in Laravel so actually maybe also you can try:

DB::table('users')
            ->join('buy_courses', 'users.user_name', '=', 'buy_courses.user_name')
            ->get();