Introduction to SQL The SELECT command, with its various clauses, allows users to query the data contained in the tables and ask many different questions or ad hoc queries. True False True False ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL What does the following query find?(SELECT DISTINCT r.sidFROM boats b, reserves rWHERE b.bid = r.bidAND b.color = 'red')MINUS(SELECT DISTINCT r.sidFROM boats b, reserves rWHERE b.bid = r.bidAND b.color = 'green') Find the sailor IDs of all sailors who have reserved red boats but not green boats Find the sailor IDs of at least one sailor who have reserved red boats but not green boats None of These Find the sailor Ids of atmost one sailor who have reserved red boats but not green boats Find the sailor IDs of all sailors who have reserved red boats but not green boats Find the sailor IDs of at least one sailor who have reserved red boats but not green boats None of These Find the sailor Ids of atmost one sailor who have reserved red boats but not green boats ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL 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 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 ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL The command to remove rows from a table 'CUSTOMER' is: DROP FROM CUSTOMER ... UPDATE FROM CUSTOMER ... REMOVE FROM CUSTOMER ... DELETE FROM CUSTOMER WHERE ... DROP FROM CUSTOMER ... UPDATE FROM CUSTOMER ... REMOVE FROM CUSTOMER ... DELETE FROM CUSTOMER WHERE ... ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL COUNT(field_name) tallies only those rows that contain a value; it ignores all null values. True False True False ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL Which of the following query finds the total rating of the sailors who have reserved boat "103"? c) SELECT COUNT(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; 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 WHERE s.sid = r.sid AND r.bid = 103 c) SELECT COUNT(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; 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 WHERE s.sid = r.sid AND r.bid = 103 ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS