Named_scope在轨唯一的记录？ [英] Named_scope in rails unique records?

问题描述

时有可能有 named_scope 返回的记录唯一的某列？

Is it possible to have named_scope return records unique for a certain column?

例如

named_scope :unique_styles, :order =>"title desc", :limit => 3

这会给我三样式，但如果我想确保标题是不同的？在这种情况下，可能有三个记录使用相同的风格，我想这named_scope为仅标题的唯一值。

That will give me three styles but what if I want to make sure the title is different? In this case there may be three records with the same style, I want this named_scope to only give unique values of title.

所以 [风格1，款式1，款式1] 是不可能的，它会迫使自己放弃 [风格1，某些样式2，也许再过3]

So ["style 1", "style 1", "style 1"] isn't possible, it'll force itself to give ["style 1", "some style 2", "maybe another 3"]

• 我觉得组可以做到这一点，我使用的是现在。如果任何人有任何意见，无论那会是巨大的。

• i think group may do it and I'm using that for now. If anyone has any comments regardless that'd be great.

推荐答案

您可能想要探索：为发现者和named_scopes组选项：

You probably want to explore the :group option for finders and named_scopes:

named_scope :unique_styles, :order => "title desc", :limit => 3, :group => "title"

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