Question

I have a Post model, with a posted boolean field.

I created a new Post, without assigning anything to posted.

irb(main):012:0> Post.first.posted
  Post Load (9.0ms)  SELECT "posts".* FROM "posts" LIMIT 1
=> nil

Now, I want to select all posts where posted is not equal to true.

I tried this, but it doesn’t work:

irb(main):016:0> Post.where("posted != ?", true)
  Post Load (2.5ms)  SELECT "posts".* FROM "posts" WHERE (posted != 't')
=> []

Any ideas?

Answer 1

It is because of how the database treats NULL. Try setting :default => false in your migration.

Depending on your database, you might see something like this: (example in MySQL)

SELECT 1 = NULL; # returns NULL
SELECT 1 != NULL; # returns NULL