Question

我不了解Rails

请问，如何在Rails中进行此查询？

SELECT *, count(v.id) numero_votos FROM ideas i left join votes v on v.idea_id = i.id group by i.id order by numero_votos desc, i.created_at

我试过了......

@listOfIdeas = Idea.find(:all, joins: "LEFT JOIN 'votes' on votes.idea_id = ideas.id",
                                    select: "ideas.*, count(votes.id) numero_de_votos",
                                    group: "ideas.id",
                                    order: "numero_de_votos DESC, ideas.created_at DESC")

但是，没有工作，它向我展示了这个信息：

无法找到所有想法＆＃39; :(全部，{：加入=＆gt;＆＃34; LEFT JOIN＆＃39;投票＆＃39;对投票.idea_id = ideas .id＆＃34;，：select =＆gt;＆＃34; ideas。*，count（votes.id）numero_de_votos＆＃34;，：group =＆gt;＆＃34; ideas.id＆＃34;，：order =＆gt ;＆＃34; numero_de_votos DESC，ideas.created_at DESC＆＃34;}）（找到0结果，但正在寻找2）

Rails版本：5.1.4

谢谢！

Answer 1

您的SQL查询看起来很奇怪。如果您的SQL查询是：

SELECT i.*, count(v.id) AS numero_votos 
FROM ideas i 
LEFT JOIN votes v ON v.idea_id = i.id 
GROUP BY i.id 
ORDER BY numero_votos DESC, i.created_at

然后，你应该尝试一下：

Idea.select("ideas.*, count(votes.id) AS numero_votos ")
    .joins("LEFT JOIN votes ON votes.idea_id = ideas.id")
    .group("ideas.id")
    .order("numero_votos DESC")
    .order("ideas.created_at")

查询 - Ruby on Rails

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