Laravel 关联关系 whereHas 跨数据库使用
Databases: db1(default)、db2 Tables: db1.a、db2.b
A.php
<?php
namespcae App\A;
class A extends model
{
    public function b()
    {
        return $this->morphToMany(B::class);
    }
}B.php
<?php
namespcae App\B;
class B extends model
{
    protected $connect = 'db2';
}How to use whereHas
A::whereHas('b', function ($query) { 
    $query->from('db2.b')->where(....); 
}); 
             
             
             
             
            