Difficulty 0
T02.001- Get all the information of users.
T02.011- Brands
Difficulty 1
T02.002- List the emails and name and surnames of the users.
T02.003- List the emails and name and surnames of the users, sorted by email.
T02.004- List the emails and name and surnames of the users, sorted by surnames and name
T02.005- List the emails and name and surnames of the users, ascending sorted by surnames and descending by name
T02.006- List the emails, name and surnames of users, descending sorted by surnames and name
T02.016- Code and retail price of the articles requested in order number 1.
T02.023- Panel of the televisions of 21 inches or less, avoiding duplicates
T02.024- Code, name, brand and retail price of the articles that have the rrp between 350 and 450.
Difficulty A
T02.025- Code, name and retail price of the articles with no brand.
T02.026- Code, name and retail price of the articles with no rpp but brand is Sigma.
T02.027- Email, name, surnames and telephone of users with name Santiago, Wencesalo or Sergio.
T02.028- Email, name, surnames and telephone of users with name Santiago, Wencesalo or Sergio, and they have telephone number.