What does <> mean in a sql query?

rubyonrails-talk
1

This is from the rails log:

SELECT "district_sets".id FROM "district_sets" WHERE ("district_sets"."ident" = 'juris-60c8bcea56c0dfa02d121691e0e72152' AND "district_sets".id <> 12) LIMIT 1

I am confused by the <> operator. Can anyone clarify that for me please? Thanks!

-- Pito

2

http://dev.mysql.com/doc/refman/5.0/en/non-typed-operators.html

not equals

3

!=

4

Fernando Perez wrote:

!=

Thanks... The reason I didn't think that is what it meant (although I believe you :slight_smile: is that I saw it here:

[Development]>> ap j #<DistrictSet:0x105568550> {                    :id => 3,          :display_name => "ds2",            :created_at => Sat, 04 Sep 2010 11:21:36 PDT -07:00,            :updated_at => Sat, 04 Sep 2010 11:21:36 PDT -07:00,        :secondary_name => nil,        :icon_file_name => nil,     :icon_content_type => nil,        :icon_file_size => nil,       :icon_updated_at => nil,      :descriptive_text => nil,                 :ident => "juris-a88e89de29712642eaef324fd9bc03ed" } => nil ## in other words, j is assigned a DistrictSet object, that has j.id = 3

[Development]>> j.save!   DistrictSet Load (0.3ms) SELECT "district_sets".id FROM "district_sets" WHERE ("district_sets"."ident" = 'juris-a88e89de29712642eaef324fd9bc03ed' AND "district_sets".id <> 3) LIMIT 1 [paperclip] Saving attachments. => true ## And when I ask activerecord to save it, I see the very odd <> 3.

Do you understand what it means?

5

I may be wrong but have you got a validates_uniqueness_of on ident? That query could be checking to see if there is already a matching ident. The id<>3 could be so that it does not find the one you are updating or creating.

Colin

6

Do you understand what it means?

It's probably a validates_uniqueness_of that adds that additional query.