查询适用于MySQL，但不适用于Postgres SQL

Question

我想知道如何在rails上查询postgress数据库？它通过MySQL的作品，但在Postgres的，它返回一个错误：

Ruby on Rails的查询

response_array = Vote. 
       by_leaderboard_date_range. 
       joins(:user). 
       joins(:event_poll_relationship). 
       select('users.*, sum(points_earned) as total'). 
       group('user_id'). 
       order('total DESC'). 
       limit(20) 

错误

2013-07-31T13:02:43.430333+00:00 app[web.3]: ActiveRecord::StatementInvalid (PG::Error: ERROR: argument of JOIN/ON must be type boolean, not type integer 
2013-07-31T13:02:43.430333+00:00 app[web.3]: LINE 1: ...ers"."id" = "votes"."user_id" LEFT JOIN events on events.esp... 
2013-07-31T13:02:43.430333+00:00 app[web.3]:               ^
2013-07-31T13:02:43.430333+00:00 app[web.3]: : SELECT users.*, sum(points_earned) as total FROM "votes" INNER JOIN "event_poll_relationships" ON "event_poll_relationships"."id" = "votes"."event_poll_relationship_id" INNER JOIN "users" ON "users"."id" = "votes"."user_id" LEFT JOIN events on events.espn_event_id WHERE (events.espn_event_id = event_poll_relationships.espn_event_id AND events.start_date_time >= '2013-07-28 00:00:00' AND events.start_date_time <= '2013-12-31 00:00:00') GROUP BY user_id ORDER BY total DESC LIMIT 20): 

VOTE模型

class Vote < ActiveRecord::Base 

    scope :by_espn_event_id, lambda {|espn_event_id| joins(:event_poll_relationship).joins('LEFT JOIN events on events.espn_event_id').where('event_poll_relationships.espn_event_id = ? AND events.espn_event_id = event_poll_relationships.espn_event_id', espn_event_id) } 
    scope :by_leaderboard_date_range, joins(:event_poll_relationship).joins('LEFT JOIN events on events.espn_event_id').where('events.espn_event_id = event_poll_relationships.espn_event_id AND events.start_date_time >= ? AND events.start_date_time <= ?',LeaderBoardRange.find(1).start_date.to_datetime,LeaderBoardRange.find(1).end_date.to_datetime) 

RAW生成的SQL

SELECT users.*, sum(points_earned) as total FROM "votes" INNER JOIN "event_poll_relationships" ON "event_poll_relationships"."id" = "votes"."event_poll_relationship_id" INNER JOIN "users" ON "users"."id" = "votes"."user_id" LEFT JOIN events on events.espn_event_id WHERE (events.espn_event_id = event_poll_relationships.espn_event_id AND events.start_date_time >= '2013-07-28 00:00:00' AND events.start_date_time <= '2013-12-31 00:00:00') GROUP BY user_id ORDER BY total DESC LIMIT 20) 

感谢

Answer 1

SOLUTION

的问题已在JOIN ON的范畴。此作品在两个DBS：MySQL的和Postgres

scope :by_espn_event_id, lambda {|espn_event_id| joins(:event_poll_relationship).joins('LEFT JOIN events ON (events.espn_event_id = event_poll_relationships.espn_event_id)').where('event_poll_relationships.espn_event_id = ?', espn_event_id) } 
    scope :by_leaderboard_date_range, joins(:event_poll_relationship).joins('LEFT JOIN events ON (events.espn_event_id = event_poll_relationships.espn_event_id)').where('events.start_date_time >= ? AND events.start_date_time <= ?',LeaderBoardRange.find(1).start_date.to_datetime,LeaderBoardRange.find(1).end_date.to_datetime) 

Ruby on Rails的查询

# calculate leaderboard by date range 
    response_array = Vote. 
     by_leaderboard_date_range. 
     joins(:user). 
     joins(:event_poll_relationship). 
     select('users.*, sum(points_earned) as total'). 
     group('users.id, user_id'). 
     order('total DESC'). 
     limit(20)