Adarq.org

Quote from: Coges on March 22, 2016, 06:13:52 pm

5am training session

 

it's really hard for me to sleep when I can't figure something out.. that's why I usually don't try and figure complex things out after 12 AM or so.

this simple piece of code took me 3 hours to figure out.. I was overlooking something for a lonnnnnng time.

Code: [Select]

q4 :: forall site.
     (YesodPersist site, YesodPersistBackend site ~ SqlBackend) =>
     Key Board -> HandlerT site IO [(E.Value Int64, E.Value Int64, E.Value Int64)]
q4 board_id = do
  runDB
    $ E.select
    $ E.from $ \((thread_post :: E.SqlExpr (Entity ThreadPost)) `E.LeftOuterJoin` (thread :: E.SqlExpr (Entity
Thread)) `E.LeftOuterJoin` (board :: E.SqlExpr (Entity Board))) -> do
      E.on $ thread ^. ThreadBoardId E.==. board ^. BoardId
      E.on $ thread_post ^. ThreadPostThreadId E.==. thread ^. ThreadId
      E.where_ $
        board ^. BoardId E.==. E.val board_id
      return (E.countDistinct $ board ^. BoardId, E.countDistinct $ thread ^. ThreadId, E.countDistinct $
thread_post ^. ThreadPostId)
now, i go lie down and die.