Rails / ActiveRecord，如何防止摘录覆盖选择？ [英] Rails/ActiveRecord, how to prevent pluck from overriding select?

问题描述

例如，我想运行一个查询

As an example, I want to run a query like

people = Person.select("GROUP_CONCAT(`first` SEPARATOR ', ') as names") \
.where(last: "smith").group(:age).order(:age)

# which basically gives me something like
# SELECT GROUP_CONCAT(`first` SEPARATOR ', ') as names ...

#####################

# but when I add pluck
people.pluck(:names)
# it does
# SELECT names ...
# and gives me an Unknown column error

我如何使rails / activerecord处理选择结果的选择

How do I make rails/activerecord to handle pluck on the result of the select query rather than overriding it?

推荐答案

这是不可能的。 pluck 将始终覆盖您指定的任何选择。但是您可以这样做：

It's not possible. pluck will always override any select you specify. But you can do this:

people = Person.where(last: "smith").group(:age).order(:age)
people.pluck("GROUP_CONCAT(`first` SEPARATOR ', ')")

或这样：

people = Person.select("GROUP_CONCAT(`first` SEPARATOR ', ') as names") \
.where(last: "smith").group(:age).order(:age)
people.all.collect(&:name)

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