Ruby-on-rails Rails 3.1 - 使用计数查找并选择为
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/8048987/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Rails 3.1 - find using count and select as
提问by Alex
I am trying to do the following sql statement in rails:
我正在尝试在 Rails 中执行以下 sql 语句：
SELECT COUNT(downloads.title) AS total, downloads.title FROM `downloads` WHERE `downloads`.`member_id` = 60 Group by `downloads`.`title`
I wrote this in rails like this:
我在 Rails 中这样写：
Download.where(:member_id => id).select("COUNT(downloads.title) AS total, downloads.title").group(:title)
If I run the query straight from the sql server the sql executes correctly but if I run the activerecord version I only get the title back.
如果我直接从 sql server 运行查询，sql 会正确执行，但如果我运行 activerecord 版本，我只会得到标题。
I thought this might be because of attr_accessible but this doesnt seem to have made a difference.
我认为这可能是因为 attr_accessible ，但这似乎没有什么不同。
any ideas ?
有任何想法吗 ？
回答by BitOfUniverse
Have you tried to call totalmethod on the collection object ?
This information is not included in the output for object using to_smethod, so you probably just do not see it, but total value is there.
您是否尝试过total在集合对象上调用方法？
此信息不包含在对象 usingto_s方法的输出中，因此您可能只是看不到它，但总价值在那里。
downloads = Download.where(:member_id => id).select("COUNT(downloads.title) AS total, downloads.title").group(:title)
downloads.first.total
