Introduction to SQL Each index consumes extra storage space and also requires overhead maintenance time whenever indexed data change value. True False True False ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL Which SQL keyword is used to retrieve only unique values? DISTINCT DISTINCTIVE DIFFERENT UNIQUE DISTINCT DISTINCTIVE DIFFERENT UNIQUE 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 All of these 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 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 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 The SQL keyword GROUP BY instructs the DBMS to group together those rows that have the same value in a column. True False True False ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL COUNT(field_name) tallies only those rows that contain a value; it ignores all null values. False True False True ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL The command to remove rows from a table 'CUSTOMER' is: UPDATE FROM CUSTOMER ... DROP FROM CUSTOMER ... REMOVE FROM CUSTOMER ... DELETE FROM CUSTOMER WHERE ... UPDATE FROM CUSTOMER ... DROP FROM CUSTOMER ... REMOVE FROM CUSTOMER ... DELETE FROM CUSTOMER WHERE ... ANSWER DOWNLOAD EXAMIANS APP
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