Rails db 中性数据透视表或交叉表
有谁知道使用 activerecord 构建数据透视表的方法，该数据透视表将是远程数据库中立的？我试图避免使用 find_by_sql 和数据库特定查询，但对于数据透视表或交叉表查询，我不知道如何以非特定于 MySQL 的方式执行此操作。 IE 我的 mySQL find_by_sql 在 postgresql 数据库上中断。
我发现 http://crosstab.rubyforge.org/ 这个晦涩的交叉表宝石可能有用，但我'我想知道其他人是否有更好的解决方案。
像这样荒谬的例子基本上只是翻转桌子上的轴：
SELECT availables.name, rooms.id,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 0, availables.price, '')) AS day1,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 1, availables.price, '')) AS day2,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 2, availables.price, '')) AS day3,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 3, availables.price, '')) AS day4,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 4, availables.price, '')) AS day5,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 5, availables.price, '')) AS day6,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 6, availables.price, '')) AS day7,
AVG(availables.price),SUM(availables.price)
FROM `availables`
INNER JOIN rooms
ON availables.room_id=rooms.id
WHERE availables.room_id = '18382'
GROUP BY availables.name
Does anyone know of a way to build a pivot table using activerecord which would be remotely DB neutral? I've tried to avoid using find_by_sql and DB specific queries but for a pivot table or crosstab query I have no idea how to do it in a way which is not specific to say MySQL. IE my mySQL find_by_sql breaks on a postgresql DB.
I found http://crosstab.rubyforge.org/ this obscure crosstab gem which might work, but I'm wondering if anyone else has a better solution.
Example something rediculous like this which basically just flips the axis on a table:
SELECT availables.name, rooms.id,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 0, availables.price, '')) AS day1,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 1, availables.price, '')) AS day2,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 2, availables.price, '')) AS day3,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 3, availables.price, '')) AS day4,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 4, availables.price, '')) AS day5,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 5, availables.price, '')) AS day6,
MAX(IF(to_days(availables.bookdate) - to_days('2009-06-13') = 6, availables.price, '')) AS day7,
AVG(availables.price),SUM(availables.price)
FROM `availables`
INNER JOIN rooms
ON availables.room_id=rooms.id
WHERE availables.room_id = '18382'
GROUP BY availables.name
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这是一个旧的但可能有用的插件：ActiveWarehouse
Here's a plugin that is old but might be useful: ActiveWarehouse