# Using conditions in ActiveRecord **URL:** \ **Category:** Rails\ **Created:** [January 18, 2006, 10:56pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770 "2006-01-18T22:56:13Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![mickey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ccd318/32.png) [@mickey](https://www.ruby-forum.com/u/mickey)\ **Post date:** [January 18, 2006, 10:56pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770/1 "2006-01-18T22:56:13Z")
This bit of code finds several groups; all those which have entity\_id’s of ‘1’ OR ‘2’ OR ‘3’, as you would expect: ee = [1, 2, 3] groups = Group.find(:all, :conditions =\> “entity\_id in (” + ee.join (",") + “)”) But this bit of code only finds groups which have entity\_id’s of ‘1’: ee = [1, 2, 3] groups = Group.find(:all, :conditions =\> [ “entity\_id in (?), ee.join (”,") ] ) Why is that? Evidently, if I switch the order like this: ee = [3, 2, 1] I only get groups with an entity\_id of ‘3’. So clearly if I specify the parameter like this ‘(?)’, I get only the first element from the ‘ee’ list included in the where clause. Why? Thanks in advance. ---
**Author:** ![mickey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ccd318/32.png) [@mickey](https://www.ruby-forum.com/u/mickey)\ **Post date:** [January 18, 2006, 11:02pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770/2 "2006-01-18T23:02:16Z")
On Jan 18, 2006, at 1:16 PM, David A. wrote: > groups = Group.find(:all, :conditions =\> [ "entity\_id in (?), > from the ‘ee’ list included in the where clause. Why? > > Thanks in advance. David- You can actually pass an array as the value to an IN query like this: groups = Group.find(:all, :conditions =\> [ "entity\_id in (?), [1,2,3] ] ) Or groups = Group.find(:all, :conditions =\> ["entity\_id in (?), ee] ) Cheers- -Ezra Z. Yakima Herald-Republic WebMaster [http://yakimaherald.com](http://yakimaherald.com) 509-577-7732 removed\_email\_address@domain.invalid ---
**Author:** ![mickey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ccd318/32.png) [@mickey](https://www.ruby-forum.com/u/mickey)\ **Post date:** [January 18, 2006, 11:05pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770/3 "2006-01-18T23:05:18Z")
2006/1/18, David A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > groups = Group.find(:all, :conditions =\> [ “entity\_id in (?), ee.join > (”,") ] ) > > Why is that? In the second case, Rails “knows” that you are providing a string, so the resulting SQL will look like: SELECT \* FROM groups WHERE entity\_id IN (‘1,2,3’) Whereas in the first case, Rails knows it’s an array, and will do the right thing. Hope that helps ! ---
**Author:** ![mickey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ccd318/32.png) [@mickey](https://www.ruby-forum.com/u/mickey)\ **Post date:** [January 18, 2006, 11:20pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770/4 "2006-01-18T23:20:23Z")
Ezra Z. wrote: > David- > You can actually pass an array as the value to an IN query like this: > > groups = Group.find(:all, :conditions =\> ["entity\_id in (?), [1,2,3] ] ) > > Or > > groups = Group.find(:all, :conditions =\> ["entity\_id in (?), ee] ) This is the method I always use to accomplish this: groups = Group.find\_all\_by\_entity\_id([1, 2, 3]) -Brian ---
**Author:** ![mickey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ccd318/32.png) [@mickey](https://www.ruby-forum.com/u/mickey)\ **Post date:** [January 19, 2006, 12:25pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770/5 "2006-01-19T12:25:15Z")
> groups = Group.find\_all\_by\_entity\_id([1, 2, 3]) Thanks for the suggestions. The plot thickens. If I do this: ee = [4, 9] Then the suggestions above both work: groups = Group.find(:all, :conditions =\> [“entity\_id in (?)”, ee] ) or groups = Group.find\_all\_by\_entity\_id(ee) return what I would expect. However, ee is created like this: ee = User.find(session[:user\_id]).entityadministrators.find(:all).map { |e| [e.id]} My understanding was that that would create an array of entity\_id’s. Indeed, it does seem to and if I join the array entries together with a comma and then use that result as a string condition in my groups query, it works. But if I just try to use the array as is, with the suggestions above, I get no rows returned. So, the question becomes, what’s the difference between: ee = User.find(session[:user\_id]).entityadministrators.find(:all).map { |e| [e.id]} # which returns a 4 and and a 9 and ee = [4, 9] ??? Thanks again. ---
**Author:** ![mickey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ccd318/32.png) [@mickey](https://www.ruby-forum.com/u/mickey)\ **Post date:** [January 19, 2006, 12:34pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770/6 "2006-01-19T12:34:21Z")
David A. wrote: > So, the question becomes, what’s the difference between: > > ee = User.find(session[:user\_id]).entityadministrators.find(:all).map { > |e| [e.id]} # which returns a 4 and and a 9 > > and > > ee = [4, 9] Just a guess: User.find(session[:user\_id]).entityadministrators.find(:all).map { |e| [e.id]} =\> [[4], [9]] User.find(session[:user\_id]).entityadministrators.find(:all).map { |e| e.id} =\> [4,9] ? ---
**Author:** ![mickey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ccd318/32.png) [@mickey](https://www.ruby-forum.com/u/mickey)\ **Post date:** [January 19, 2006, 4:35pm UTC](https://www.ruby-forum.com/t/using-conditions-in-activerecord/52770/7 "2006-01-19T16:35:48Z")
> User.find(session[:user\_id]).entityadministrators.find(:all).map { | > e| e.id} =\> [4,9] Right! This works (i.e. removing the extra square brackets in the first array creation): @ee = User.find(session[:user\_id]).entityadministrators.find (:all, :order =\> “id asc”).map { |e| e.id} @groups = Group.find(:all, :conditions =\> ["entity\_id in (?) ", @ee]) Many thanks.