使用Laravel查询生成器联接3个表

Question

I am trying to implement a reshare action button on a message posting website that I am working on and output those reshared message along with the messages that users have posted recently.

For the time being I have a USERS table and a MESSAGES table. And in order to retrieve recently posted messages I use the below query.

return DB::table('messages')
->join('users', 'users.username', '=', 'messages.username')
->select('users.username as username','messages.id as id','messages.message as message', 'users.firstName as firstName','users.lastName as lastName') ->orderBy('messages.id', 'desc')
->paginate(20);

But now I have added a RESHARES table in which I store username of the person who reshared the message and the message_id . So what I really want to know is how do I join these tables and retrieve both reshared message and recently posted messages.

Please do post your answer in relartion to Laravel Query Builder .

Answer 1

You can simply add another join to your query.

DB::table(...)
->join(table2...)
->join(table3...)
->select(...)
->paginate(...)

and query for the additional columns exactly as you do in your query right now.

As not every message might be reshared, you should consider using a left join for your reshares table. You can do so by using

->leftJoin()

again, exactly the way you do right now.