Introduction to SQL Which of the following group functions ignore NULL values? SUM All of these MAX COUNT SUM All of these MAX COUNT 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 The SQL -92 wildcards are ____ and ____ . underscore(_); question mark (?) percent sign (%); underscore (_) question mark (?); asterisk (*) asterisk (*); percent sign (%) underscore(_); question mark (?) percent sign (%); underscore (_) question mark (?); asterisk (*) asterisk (*); percent sign (%) 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 HAVING clause acts like a WHERE clause, but it identifies groups that meet a criterion, rather than rows. True False True False ANSWER DOWNLOAD EXAMIANS APP
Introduction to SQL There is an equivalent join expression that can be substituted for all subquery expressions. True False True False ANSWER DOWNLOAD EXAMIANS APP
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