Question

我的rails应用程序中有一个相当复杂的查询，我加入表A和表B，这样我就可以彻底搜索两个表然后，我在其ID上对表A进行分组，以删除由表B上的内部联接创建的重复项然后我要求剩余记录的计数，以便我可以对结果进行分页。

但是当我尝试计算时，这样做会给我以下异常：

ActiveRecord::StatementInvalid (PG::AmbiguousColumn: ERROR:  column reference "game_id" is ambiguous
LINE 1: SELECT COUNT(*) AS count_all, game_id AS game_id, region AS ...
                                      ^
: SELECT COUNT(*) AS count_all, game_id AS game_id, region AS region FROM "game_data" INNER JOIN "player_participants" ON "player_participants"."game_id" = "game_data"."game_id" WHERE "player_participants"."region" = $1 AND "game_data"."region" = 'NA1' AND "game_data"."status" = 1 GROUP BY "game_data"."game_id", "game_data"."region"):

这是我的导轨代码：

games = GameDatum.joins(:player_participants).where(
  player_participants: pp_data,
  game_data: g_data
).group(:game_id).order(created_at: :desc).page(page).per(records)

games_json = {}
games_json[:pages] = games.total_pages

games.total_pages使用.count，这就是给我带来问题的。

感谢您的帮助！

Answer 1

ERROR:  column reference "game_id" is ambiguous

您的两个表中看起来都有game_id列。因此，在查询中使用table_name.column_name约定。如果您想使用.group('player_participants.game_id')表格中的group(:game_id)，请使用game_id代替player_participants：

  games = GameDatum
    .joins(:player_participants)
    .where(player_participants: pp_data, game_data: g_data)
    .group('player_participants.game_id')
    .order(created_at: :desc)
    .page(page)
    .per(records)

Answer 2

从纯SQL答案来看，问题是game_id出现在两个表中，因此您需要在查询中具体使用，例如：

SELECT COUNT(*) AS count_all, "player_participants".game_id AS game_id, region AS region FROM "game_data" INNER JOIN "player_participants" ON "player_participants"."game_id" = "game_data"."game_id" WHERE "player_participants"."region" = $1 AND "game_data"."region" = 'NA1' AND "game_data"."status" = 1 GROUP BY "game_data"."game_id", "game_data"."region"

因此，我建议您尝试将table.column_name添加到您的论坛，例如：

。集团（＆＃39; player_participants.game_id＆＃39）

很抱歉，我无法提供更多帮助。

获取已连接和分组查询中的总行数

2 个答案: