我怎样才能获得通过的ActiveRecord＃查找创建的SQL语句，而无需实际执行呢？ [英] How can I get SQL statement created by ActiveRecord#find without actually executing it?

问题描述

我使用 will_paginate 有一些复杂的查询，这是无法正确计算（以显示页面链接适当数量）总记录数 - 因为即分组由多个列。

I am using will_paginate with some complicated queries and it is unable to correctly calculate number of total records (in order to display proper number of page links) - namely because of grouping by multiple columns.

所以，我打算让SELECT查询，它会被用于检索的所有记录，没有实际执行它，并用 SELECT COUNT（*）FROM ... 手动，为了得到的记录数

So, I am intending to get the SELECT query which would be used to retrieve ALL records, without actually executing it, and wrap it with SELECT COUNT(*) FROM ... manually, in order to get the number of records.

任何想法怎么办呢？

编辑：我使用Rails 2.3.x

I am using Rails 2.3.x

推荐答案

这似乎thatm在Rails的2.X，一个私有方法称为<一个href="http://apidock.com/rails/ActiveRecord/Base/construct_finder_sql/class"><$c$c>ActiveRecord::Base#construct_finder_sql也可以使用，我需要更多的测试，看看它是否会为我工作：

It seems thatm in Rails 2.x, a private method called ActiveRecord::Base#construct_finder_sql could be used, I need to test it more and see whether it will work for me:

ActionType.find(:all, :select => 'hosted, top_action_type, count(*) as count', :group => 'hosted, top_action_type').count
#=> 6
sql = ActionType.send :construct_finder_sql, :select => 'hosted, top_action_type, count(*) as count', :group => 'hosted, top_action_type'
#=> "SELECT hosted, top_action_type, count(*) as count FROM "action_types"  GROUP BY hosted, top_action_type"
ActionType.count_by_sql "SELECT COUNT(*) FROM (#{sql}) a"
#=> 6

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