Question

I have a query in my rails application,

      user_info = Information.where("user_id = ? and department_id NOT IN (?)",user.id,     Department.unapproved_departments ).all(:include => [:name, :project]).

Here unapproved_departments contains an array of ids in Department table.

The problem arises when unapproved_departments is a blank array.In those cases “NOT IN”
checks for ids present in the array and entire user_info is returned as a blank array.
So i would like to have all the data with ids other than those in unapproved_departments array or you can say an alternative for NOT IN

Thanx

Answer 1

Theres nothing wrong with NOT IN — just that you don’t want it to fire when there’s nothing there.

I suggest:

  user_info = Information.where("user_id = ?", user)

  unapproved_departments = Department.unapproved_departments
  if unapproved_departments.present?   # true if not blank or nil
    user_info = user_info.where("department_id NOT IN (?)", unaproved_departments) 
  end
  user_info.all(:include => [:name, :project])

As you can see, you can chain the conditions together.