Laravel hasManyThrough

hasManyThrough根本不是办法.它只适用于这样的关系:

A hasMany/hasOne B, B hasMany/hasOne C, then A hasManyThrough C (through B)

What you have here is a many to many (belongsToMany), with meta being the pivot table.

So you can do this (assuming meta is table name, Booking and MetaType are models):

// Booking model
public function meta()
{
  return $this->belongsToMany('MetaType', 'meta', 'booking_id', 'metatype_id')
        ->withPivot([ ARRAY OF FIELDS YOU NEED FROM meta TABLE ]);
}

Then you can access all associated MetaType:

$booking->meta; // collection of MetaType models

query it like this (eager loading):

$booking = Booking::with(['meta' => function ($q) {

  // query related table
  $q->where('someFieldOnMetaTypeTable', 'someValue')

    // and / or pivot table
    ->wherePivot('someFieldOnMetaTable', 'anotherValue');

}])->first();

或在相关表格上设置约束以过滤预订:

$booking = Booking::whereHas('meta', function ($q) {

  // query related table
  $q->where('someFieldOnMetaTypeTable', 'someValue')

    // and / or pivot table
    ->where('meta.someFieldOnMetaTable', 'anotherValue');

})->first();

Note: wherePivot works only when you eager load the relationship, so you can't use it in whereHas closure.