# Collection\_select unique value

**URL:** <https://www.ruby-forum.com/t/collection-select-unique-value/126366>\
**Category:** Rails\
**Created:** [January 17, 2008, 7:23pm UTC](https://www.ruby-forum.com/t/collection-select-unique-value/126366 "2008-01-17T19:23:54Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![joan2kus](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9fc29f/32.png) [@joan2kus](https://www.ruby-forum.com/u/joan2kus)\
**Post date:** [January 17, 2008, 7:23pm UTC](https://www.ruby-forum.com/t/collection-select-unique-value/126366/1 "2008-01-17T19:23:54Z")

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I have a table named “posts” with an “author” attribute. At the posts  
index page, the user should be able to sort the posts through a drop  
down list that contains the author name.

My problem is, when I use form option helper “collection\_select”, it  
gives me all the authors that contained in the “field” - 3 Johns and 4  
Chris -. How can I remove the duplicates from the drop down list?