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我正在尝试与以下 2 个查询相交，但出现此错误：

ProgrammingError：（ProgrammingError）（1064，“您的 SQL 语法有错误；请查看与您的 MySQL 服务器版本相对应的手册，以获取正确的语法，以便在 'INTERSECT SELECT user_checkpoint.id AS user_checkpoint_id, user_checkpoint.user_' 行附近使用4" ）“SELECT anon_1.user_checkpoint_id AS anon_1_user_checkpoint_id，anon_1.user_checkpoint_user_id AS anon_1_user_checkpoint_user_id，anon_1.user_checkpoint_checkpoint_id AS anon_1_user_checkpoint_checkpoint_id，anon_1.user_checkpoint_date_added AS anon_1_user_checkpoint_date_added \ n从（SELECT user_checkpoint.id AS user_checkpoint_id，user_checkpoint.user_id AS user_checkpoint_user_id，user_checkpoint.checkpoint_id AS user_checkpoint_checkpoint_id，用户检查点。date_added AS user_checkpoint_date_added \nFROM user_checkpoint INNER JOIN checkpoint ON checkpoint.id = user_checkpoint.checkpoint_id INNER JOIN user AS user_1 ON user_checkpoint.user_id = user_1.id INNER JOIN facebook_user AS facebook_user_1 ON facebook_user_1.id = user_1.facebook_user_id INNER JOIN friend_connection ONfriend_connection.fb_user_to = facebook_user_1.id INNER JOIN facebook_user ON facebook_user.id =friend_connection.fb_user_from INNER JOIN user ON user.facebook_user_id = facebook_user.id \nWHERE user.id != %s AND checkpoint.creator = user_1.id AND checkpoint.demo = %s交叉选择 user_checkpoint.id AS user_checkpoint_id, user_checkpoint.user_id AS user_checkpoint_user_id, user_checkpoint.checkpoint_id AS user_checkpoint_checkpoint_id, user_checkpoint。date_added AS user_checkpoint_date_added \nFROM user_checkpoint INNER JOIN checkpoint ON checkpoint.id = user_checkpoint.checkpoint_id \nWHERE checkpoint.creator != %s AND checkpoint.demo = %s) AS anon_1 ORDER BY checkpoint.date_created DESC \n LIMIT %s' (185L , 0, 185L, 0, 1)

    #get checkpoints from users with friends
    FriendUserCheckpoint, FriendFacebookUser, FriendUser = aliased(UserCheckpoint), aliased(FacebookUser), aliased(User)
    q = (db.session.query(UserCheckpoint).
         join(Checkpoint, Checkpoint.id == UserCheckpoint.checkpoint_id).
         join(FriendUser, FriendUser.id == UserCheckpoint.user_id).
         join(FriendFacebookUser, FriendFacebookUser.id == FriendUser.facebook_user_id).
         join(FriendConnection, FriendConnection.fb_user_to == FriendFacebookUser.id).
         join(FacebookUser, FacebookUser.id == FriendConnection.fb_user_from).
         join(User, User.facebook_user_id == FacebookUser.id).
         filter(User.id != user_obj.id).
         filter(Checkpoint.creator == FriendUser.id).
         filter(Checkpoint.demo == False)
         )

    #get checkpoints from users without friends
    p = (db.session.query(UserCheckpoint).
         join(Checkpoint, Checkpoint.id == UserCheckpoint.checkpoint_id).
         filter(Checkpoint.creator != user_obj.id).
         filter(Checkpoint.demo == False)
         )

    w = q.intersect(p)

    return w.order_by(desc(Checkpoint.date_created)).limit(limit).all()

我该如何解决？谢谢！

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1 回答 1

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您的查询的问题是order_by：您尝试按不在查询中的列进行排序。您生成的SQL查询如下所示：

SELECT anon_1.col1, anon_1.col2, ...
FROM (
    SELECT  <UserCheckpoint columns>
    FROM    UserCheckpoint
    ... (joins, filters etc)


    INTERSECT

    SELECT  <UserCheckpoint columns>
    FROM    UserCheckpoint
    ... (joins, filters etc)
) anon_1
ORDER BY checkpoint.date_created DESC -- @note: here is the problem

如您所见，外部查询checkpoint的源表列表中没有表（仅包含一个表 anon_1）。删除order_by，我假设您的查询将起作用。

如果您需要 order_by，则更改查询以返回该date_created列，对结果进行排序，然后稍后删除该列：

q = (db.session.query(UserCheckpoint, Checkpoint.date_created).
...
p = (db.session.query(UserCheckpoint, Checkpoint.date_created).
...
return [uc for (uc, _) in w.order_by(desc(Checkpoint.date_created)).limit(limit).all()]
于 2012-05-21T14:15:29.657 回答