Hi all,
I am trying to run a query like this one, using sqlalchemy:
SELECT
t.`ForumID`,
( SELECT `ID` FROM `posts` p WHERE `ThreadID` = t.`ID` ORDER BY p.`Date`
DESC LIMIT 1 ) as `LastPost`
FROM `threads` t
WHERE t.`Deleted` = 0
I am unsure how to achieve the subquery that comes out as 'LastPost'.
Closest I have gotten is this:
lastPostQ =
s.query(db.Post.ID).filter(db.Post.ThreadID==db.Thread.ID).order_by(desc(db.Post.Date)).limit(1).label("LastPost")
q = s.query(
db.Thread.ForumID,
lastPostQ
).\
join(db.Forum, db.Forum.ID==db.Thread.ForumID).\
join(db.ForumPermission, db.ForumPermission.ForumID==db.Thread.ForumID).\
filter(db.Thread.Deleted==0)
Which generates the following SQL:
SELECT
threads."ForumID" AS "threads_ForumID",
(SELECT posts."ID" FROM posts, threads WHERE posts."ThreadID" =
threads."ID" ORDER BY posts."Date" DESC LIMIT :param_1) AS "LastPost"
FROM
threads
WHERE
threads."Deleted" = :Deleted_1
Which is close, but the subqueries select statement is selecting "FROM
posts, threads" where it should only be "FROM posts".
I don't know how to procede from here. A member on IRC suggested
using correlate() but I am unsure as how or where to use it, as the
documentation was unclear.
Any help would be appreciated!
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