多对多关系查询

Question

I got 3 main table.

Table A Table B Table C

Table A has many to many relationships with Table B so they have a pivot table ab

Table B has also many to many relationships with Table C so they also have a pivot table bc

So because of this Table A has many to many through, relationship with Table C.

So what is the MySQL query if I wanted to get all rows of Table C that is related to Table A?

Answer 1

You work backwards:

$tableAID = 1;

TableC::whereHas('tableB', function($q) use ($tableAID) {
    $q->whereHas('tableA', function($q) use ($tableAID) {
        $q->where('id', $tableAID);
    });
})->get();

Answer 2

If you set the models well, A->Bs->Cs; should do the trick.