Hi Luke,
If I want to find all rows in a table where a field matches one of several possible values, what is the most efficient way to do it?
So I have table groups, with field idcode I have idcodes = [143, 482, 941] I'm guessing I should do:
find(:all, :conditions => idcodes.collect {|id| "idcode = #{id}"}.join(" OR "))
find :all, :conditions => [ 'idcode IN (?)', idcodes]
is better.
And don't use string interpolation in tour queries to avoid possible SQL injection.
Oh, and I suppose instead of making two posts, since they are directly related, I can just ask another question here also:
I'm going to be getting the array of idcodes from another table, called idents.
Something like table idents, with fields name, code1, code2, idcode.
I want to get an array of all the idcodes where the row fits some other condition... should I do this via find(:all, :conditions => "code1 = 2 AND code2 = 4").collect {|ident| ident.idcode}, or is there some other, better way to get an array containing just the values of one field of a table, without having to get each record and pull that field from it?
if you're only interested in idcode attribute, I can only see to fetch only idcode attribute with :select option like this :
find(:all, :conditions => "...", :select => 'idcode').map(&:idcode)
the map(&:idcode) is the same as your collect ... but shorter 
-- Jean-François.
