如何在不实际执行的情况下获取由 ActiveRecord#find 创建的 SQL 语句? [英] How can I get SQL statement created by ActiveRecord#find without actually executing it?

问题描述

我将 will_paginate 用于一些复杂的查询，但无法正确计算总记录数(以显示适当数量的页面链接) - 即因为按多列分组.

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，我打算获取用于检索所有记录的 SELECT 查询，而不实际执行它，并用 SELECT COUNT(*) FROM ... 手动包装它，在以获取记录数.

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.

知道怎么做吗?

我使用的是 Rails 2.3.x

I am using Rails 2.3.x

推荐答案

对于 Rails 3:

For Rails 3:

在 Rails 3 文档中查看 ActiveRecord::Relation 文档.

Check out the ActiveRecord::Relation docs at the Rails 3 docs.

# get the relation
rel = User.complex_scope.chained_complex_scope

# get the SQL
# this does not execute the query
sql = rel.to_sql

# find out how many records
# this executes the query behind the scenes
count = rel.size

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