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Mobile Computing Applications

CS 284 (MCA), Interim 2018

Example - sailors

%  psql mca_i18 -h shelob.cs.stolaf.edu

  • 1. Find the names of sailors who have reserved boat number 103

  • 2. Find the names of sailors who have reserved a red boat

  • 3. Find the colors of boats reserved by Lubber

  • 4. Find the names of sailors who have reserved at least one boat

  • 5. Find the names of sailors who have reserved a red or a green boat

  • 6. Find the names of sailors who have reserved both a red and a green boat

  • 9. Find the names of sailors who have reserved all boats.

  • 11. Find all sailors with a rating above 7.

  • 15. Find the names and ages of all sailors

  • 16. Find the sids of sailors who have reserved a red boat.

  • 17. Compute increments for the ratings of persons who have sailed two different boats on the same day.

EXCEPT,UNION

  • 19. Find sids of all sailors who have reserved red boats but not green boats.

  • 20. Find all sids of sailors who have a rating of 10 or have reserved boat 104.

  • 21. Find the names of sailors who have NOT reserved a red boat.

Aggregates

  • 22. Find sailors whose rating is better than some sailor called Horatio.

  • 23. Find sailors whose rating is better than every sailor called Horatio.

  • 24. Find the sailors with the highest rating.

  • 25. Find the average age of all sailors.

  • 26. Find the average age of all sailors with a rating of 10.

  • 27. Find the name and age of the oldest sailor.

  • 28. Count the number of sailors.

  • 29. Count the number of different sailor names.

  • 30. Find the names of sailors who are older than the oldest sailor with a rating of 10.

GROUP BY, HAVING

  • 31. Find the age of the youngest sailor for each rating level.

  • 32. Find the age of the youngest sailor who is elegible to vote (at least 18 years old) for each rating level with at least two such sailors.

  • 33. For each red boat, find the number of reservations for that boat.

  • 34. Find the average age of sailors for each rating level that has at least two sailors.

  • 35. Find the average age of sailors who are of voting age (at least 18 years old) for each rating level that has at least two sailors.

  • 36. Find the average age of sailors who are of voting age (at least 18 years old) for each rating level that has at least two such sailors.

  • 37. Find those ratings for which the average age of sailors is the minimum over all ratings.