Introduction to SQL Each index consumes extra storage space and also requires overhead maintenance time whenever indexed data change value. False True False True ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL There is an equivalent join expression that can be substituted for all subquery expressions. False True False True ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL 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 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 c) SELECT COUNT(s.rating) FROM sailors s, reserves r WHERE s.sid = r.sid AND r.bid = 103 ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL The SELECT statement SELECT 'Hi' FROM DUAL WHERE NULL = NULL; Outputs Hi Nothing FLASE TRUE Hi Nothing FLASE TRUE 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? 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 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 ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL If you are going to use a combination of three or more AND and OR conditions, it is often easier to use the NOT and NOT IN operators. True False True False ANSWER DOWNLOAD EXAMIANS APP
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