# "Not unique table/alias" errors when upgrading to Rails 2.1

**URL:** <https://www.ruby-forum.com/t/not-unique-table-alias-errors-when-upgrading-to-rails-2-1/139365>\
**Category:** Rails\
**Created:** [June 3, 2008, 9:45am UTC](https://www.ruby-forum.com/t/not-unique-table-alias-errors-when-upgrading-to-rails-2-1/139365 "2008-06-03T09:45:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Olly\_L](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/eb8c5e/32.png) [@Olly\_L](https://www.ruby-forum.com/u/Olly_L)\
**Post date:** [June 3, 2008, 9:45am UTC](https://www.ruby-forum.com/t/not-unique-table-alias-errors-when-upgrading-to-rails-2-1/139365/1 "2008-06-03T09:45:06Z")

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Hi

I’ve just attempted an upgrade from Rails 2.02 to 2.1 and I’m seeing  
dozens of unit test failures with errors like this:

ActionView::TemplateError: Mysql::Error: Not unique table/alias:  
‘clients’: SELECT count(DISTINCT `projects`.id) AS count\_all FROM  
`projects` LEFT OUTER JOIN `clients` ON `clients`.id =  
`projects`.client\_id INNER JOIN clients ON projects.client\_id =  
clients.id WHERE ((`clients`.company\_id = 1) AND  
((projects.status = ‘Active’)))

This is invalid SQL which Rails has generated – it seems to be the  
‘INNER JOIN clients ON projects.client\_id = clients.id’ which is  
causing the problem, but I can’t figure out why this is happening.

Has anyone else experienced a similar problem with Rails 2.1, or can  
anyone suggest what new features of 2.1 might be responsible for  
introducing these errors?

Many thanks  
Olly

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<div class="post-metadata">

**Author:** ![Olly\_L](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/eb8c5e/32.png) [@Olly\_L](https://www.ruby-forum.com/u/Olly_L)\
**Post date:** [June 3, 2008, 10:14am UTC](https://www.ruby-forum.com/t/not-unique-table-alias-errors-when-upgrading-to-rails-2-1/139365/2 "2008-06-03T10:14:02Z")

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On Jun 3, 8:44 am, Olly L. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Hi
> 
> I’ve just attempted an upgrade from Rails 2.02 to 2.1 and I’m seeing  
> dozens of unit test failures with errors like this:

What’s the code that produces that error?

Fred

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<div class="post-metadata">

**Author:** ![Olly\_L](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/eb8c5e/32.png) [@Olly\_L](https://www.ruby-forum.com/u/Olly_L)\
**Post date:** [June 3, 2008, 10:34am UTC](https://www.ruby-forum.com/t/not-unique-table-alias-errors-when-upgrading-to-rails-2-1/139365/3 "2008-06-03T10:34:07Z")

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On Jun 3, 9:12 am, Frederick C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> What’s the code that produces that error?

I believe it’s this declaration:

has\_many :active\_projects,  
:through =\> :clients,  
:source =\> :projects,  
:conditions =\> “projects.status = ‘Active’”,  
:order =\> “ends\_on DESC”,  
:include =\> :client