activerecord - How to compare null in rails active record query -

how can match null in rails active record.

user.where(['id = ? , active = ? , activation_code = ?', params[:id], 0, null]).first 

or

 user.where(['id = ? , active = ? , activation_code = ?', params[:id], 0, nil]).first 

both not working.

try this:

user.where(['id = ? , active = ? , activation_code null', params[:id], 0]).first