[5.6] Adding fromSub and fromRaw methods to query Builder

[henriquepedrosa]

Added

• fromSub and fromRaw methods to Query Builder so the user can create a subquery on "from", instead of only being able to use table names.

Example

$builder->fromSub(function ($query) {
    $query->select(new Raw('max(last_seen_at) as last_seen_at'))->from('user_sessions')->where('foo', '=', '1');
}, 'sessions')->where('bar', '<', '10');

This creates the following sql:

select * from (select max(last_seen_at) as last_seen_at from "user_sessions" where "foo" = ?) as "sessions" where "bar" < ?

[taist24]

How to add an alias to the derived table when using fromRaw()?

1.) Union Query

$postLikes = DB::table($table, 'n')
    ->select('n.*', 'reference_id AS post_id', DB::raw('NULL AS comment'))
    ->where('type', AppNotification::LIKE_POST_NOTIFICATION);

$postComments = DB::table($table, 'n')
    ->select('n.*', 'pc.post_id', 'pc.comment')
    ->join('post_comments AS pc', 'n.reference_id', '=', 'pc.id')
    ->where('type', AppNotification::COMMENT_ON_POST_NOTIFICATION);

$postCommentReplies = DB::table($table, 'n')
    ->select('n.*', 'pc.post_id', 'pcr.reply')
    ->join('post_comment_replies AS pcr', 'n.reference_id', '=', 'pcr.id')
    ->join('post_comments AS pc', 'pcr.post_comment_id', '=', 'pc.id')
    ->where('type', AppNotification::REPLY_ON_POST_NOTIFICATION);

$unionOfAllTables = $postLikes->union($postComments)->union($postCommentReplies);

Output

# Outputs:
----------
(select `n`.*, `reference_id` as `post_id`, NULL AS comment from `app_notifications` as `n` where `type` = ?)
union
(select `n`.*, `pc`.`post_id`, `pc`.`comment` from `app_notifications` as `n` inner join `post_comments` as `pc` on `n`.`reference_id` = `pc`.`id` where `type` = ?)
union
(select `n`.*, `pc`.`post_id`, `pcr`.`reply` from `app_notifications` as `n` inner join `post_comment_replies` as `pcr` on `n`.`reference_id` = `pcr`.`id` inner join `post_comments` as `pc` on `pcr`.`post_comment_id` = `pc`.`id` where `type` = ?)

2. Using fromRaw() with the above union query

$data = DB::query()->fromRaw("({$unionOfAllTables->toSql()})", $unionOfAllTables->getBindings())->get();

Output

select * from (
  (select `n`.*, `reference_id` as `post_id`, NULL AS comment from `app_notifications` as `n` where `type` = ?)
  union
  (select `n`.*, `pc`.`post_id`, `pc`.`comment` from `app_notifications` as `n` inner join `post_comments` as `pc` on `n`.`reference_id` = `pc`.`id` where `type` = ?)
  union
  (select `n`.*, `pc`.`post_id`, `pcr`.`reply` from `app_notifications` as `n` inner join `post_comment_replies` as `pcr` on `n`.`reference_id` = `pcr`.`id` inner join `post_comments` as `pc` on `pcr`.`post_comment_id` = `pc`.`id` where `type` = ?)
) // <--- Notice the error here as it's missing the alias for the derived table

[walidbagh]

both those methods are not documented ...

[vserdobintsev]

Please add to documentation