The support team logs tickets. A mistake? Click Reset lab and create the table again.

1. Create tickets with three columns:
   • id: a whole number that only the database gives; an INSERT that gives an id must fail
   • subject: text, required
   • opened_on: a date, required; today when the INSERT does not say
2. Add three tickets with one INSERT: Lost parcel, Wrong size and Broken mug.
3. Add a ticket with id 100 and the subject Test. The database refuses it. The DETAIL line ends with two words that say why. Which two?
4. Add a ticket whose subject is NULL, and read the error. Then add the ticket Late delivery.
5. Look at the tickets tab. Which id between 1 and the newest one is missing?