# Validation: comparing two fields

**URL:** <https://discuss.rubyonrails.org/t/validation-comparing-two-fields/4589>\
**Category:** rubyonrails-talk\
**Created:** [November 16, 2006, 12:12am UTC](https://discuss.rubyonrails.org/t/validation-comparing-two-fields/4589 "2006-11-16T00:12:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Josh\_Stephenson](https://avatars.discourse-cdn.com/v4/letter/j/a698b9/32.png) [@Josh\_Stephenson](https://discuss.rubyonrails.org/u/Josh_Stephenson)\
**Post date:** [November 16, 2006, 12:12am UTC](https://discuss.rubyonrails.org/t/validation-comparing-two-fields/4589/1 "2006-11-16T00:12:40Z")

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in your model

protected def validate &nbsp;&nbsp;errors.add(:end\_date, "can't come before the Start date") if end\_date \< start\_date end