sql mcq Questions and answers

1 . Which of the following query finds the total rating of the sailors who have reserved boat "103"?

  • SELECT SUM(s.rating) FROM sailors s, reserves r WHERE s.sid = r.sid AND r.bid = 103
  • SELECT COUNT(s.rating) FROM sailors s, reserves r WHERE s.sid = r.sid AND r.bid = 103
  • SELECT s.rating FROM sailors s, reserves r WHERE s.sid = r.sid AND r.bid = 103
  • SELECT SUM(s.rating) FROM sailors s, reserves r AND r.bid = 103

2 . The SELECT statement SELECT 'Hi' FROM DUAL WHERE NULL = NULL; Outputs
  • NO
  • TRUE
  • FALSE
  • NONE

3. Which of the following is illegal?
  • SELECT SYSDATE - SYSDATE FROM DUAL
  • SELECT SYSDATE - (SYSDATE - 2) FROM DUAL
  • SELECT SYSDATE - (SYSDATE + 2) FROM DUAL
  • None

4 . If a query involves NOT, AND, OR with no parenthesis:
  • NOT will be evaluated first; AND will be evaluated second; OR will be evaluated last
  • NOT will be evaluated first; OR will be evaluated second; AND will be evaluated last
  • The order of occurrence determines the order of evaluation
  • AND will be evaluated first; OR will be evaluated second; NOT will be evaluated last


5. Find the name of cities with all entries whose temperature is in the range of 71 and 89:
  • FROM weather WHERE temperature NOT IN (71 to 89)
  • FROM weather WHERE temperature NOT IN (71 and 89)
  • FROM weather WHERE temperature NOT BETWEEN 71 to 89
  • FROM weather WHERE temperature BETWEEN 71 AND 89


6 . Which of the following query finds the names of the sailors who have reserved at least one boat?
  • SELECT DISTINCT s.sname FROM sailors s, reserves r WHERE s.sid = r.sid
  • SELECT s.sname FROM sailors s, reserves r WHERE s.sid = r.sid
  • SELECT DISTINCT s.sname FROM sailors, reserves WHERE s.sid = r.sid
  • None


7 . Which of the following query finds colors of boats reserved by "Dustin"?
  • SELECT DISTINCT b.color FROM boats b, sailors s WHERE s.sname = 'Dustin' AND s.sid = b.sid
  • SELECT DISTINCT b.color FROM boats b, reserves r, sailors s WHERE s.sname = 'Dustin' AND s.sid = r.sid AND r.bid = b.bid
  • SELECT DISTINCT b.color FROM boats b, reserves r, sailors s WHERE s.sname = 'Dustin' AND s.sid = r.sid
  • SELECT DISTINCT b.color FROM boats b, reserves r, sailors s WHERE s.sname = 'Dustin' AND r.bid = b.bid


8 . Which of the following query finds the name of the sailors who have reserved at least two boats?
  • SELECT DISTINCT s.sname FROM sailors s, reserves r1, reserves r2 WHERE s.sid = r1.sid AND r1.sid = r2.sid AND r1.bid ≠ r2.bid
  • SELECT DISTINCT s.sname FROM sailors s, reserves r1, reserves r2 WHERE s.sid = r1.sid AND COUNT(r1.bid) > r2.bid
  • SELECT DISTINCT s.sname FROM sailors s, reserves r1, reserves r2 WHERE s.sid = r1.sid AND r1.sid = r2.sid AND r1.bid <> r2.bid
  • All of these

9 . Which command undo all the updates performed by the SQL in the transaction?
  • ROLLBACK
  • COMMIT
  • TRUNCATE
  • DELETE

10. Find all the cities whose humidity is 89:
  • SELECT city WHERE humidity = 89
  • SELECT city FROM weather WHERE humidity = 89
  • SELECT humidity = 89 FROM weather
  • SELECT city FROM weather

































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