使用查找的 Rails SQL 查询 [英] Rails SQL Query with find

问题描述

我希望在 rails 控制器中使用 find 编写这个 SQL 查询:

I want this SQL query to be written in rails controller using find:

select id,name from questions
where id not in (select question_id from levels_questions where level_id=15)

我将如何做到这一点?我正在使用 Rails 框架和 MySQL.提前致谢.

How will I do this? I am using Rails framework and MySQL. Thanks in advance.

推荐答案

简单方法:

ids = LevelsQuestion.all(:select => "question_id", 
        :conditions => "level_id = 15").collect(&:question_id)
Question.all(:select => "id, name", :conditions => ["id not in (?)", ids])

一枪:

Question.all(:select => "id, name",
:conditions => ["id not in (select question_id from levels_questions where level_id=15)"])

这篇关于使用查找的 Rails SQL 查询的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！