#14 Performing Calculations on Models

最新推荐文章于 2024-09-30 08:05:46 发布

原创最新推荐文章于 2024-09-30 08:05:46 发布 · 173 阅读

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#ActiveRecord #Java

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本文介绍ActiveRecord提供的类方法，用于对模型执行计算操作，包括求和、最大值、最小值和平均值等，并展示了如何通过条件筛选进行计算。

Did you know ActiveRecord provides class methods for performing calculations on models? You can even use these methods through associations.


Task.sum(:priority)
Task.sum(:priority, :conditions => 'complete=0')
Task.maximum(:priority)
Task.minimum(:priority)
Task.average(:priority)
p = Project.find(:first)
p.tasks.sum(:priority)
p.tasks.sum(:priority, :conditions => 'complete=0')

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