MariaDB [toyu]> SELECT DISTINCT s.fname, s.lname, -> d.deptName AS `Major department` -> FROM student AS s INNER JOIN department AS d ON (s.major = d.deptCode) -> INNER JOIN enroll AS e ON (s.stuId = e.stuId) -> INNER JOIN class AS c ON (e.classId = c.classId) -> INNER JOIN faculty AS f ON (c.facId = f.facId) -> WHERE c.facId AND f.deptCode = 'CSCI'; +---------+---------+------------------------------+ | fname | lname | Major department | +---------+---------+------------------------------+ | Tony | Hawk | Computer Science | | Mary | Hawk | Computer Science | | David | Hawk | Computer Science | | Larry | Johnson | Information Technology | | Linda | Johnson | Computer Information Systems | | Lillian | Johnson | Computer Information Systems | +---------+---------+------------------------------+ 6 rows in set (0.013 sec) MariaDB [toyu]> SELECT DISTINCT e.stuId -> FROM enroll; ERROR 1054 (42S22): Unknown column 'e.stuId' in 'field list' MariaDB [toyu]> SELECT DISTINCT e.stuId -> FROM enroll AS e; +--------+ | stuId | +--------+ | 100000 | | 100001 | | 100002 | | 100004 | | 100005 | | 100006 | | 100007 | | 100008 | +--------+ 8 rows in set (0.001 sec) MariaDB [toyu]> SELECT DISTINCT s.stuId, CONCAT(s.fname, ' ', s.lname) AS student -> FROM student AS s INNER JOIN enroll AS e ON (s.stuId = e.stuId); +--------+-----------------+ | stuId | student | +--------+-----------------+ | 100000 | Tony Hawk | | 100001 | Mary Hawk | | 100002 | David Hawk | | 100004 | Larry Johnson | | 100005 | Linda Johnson | | 100006 | Lillian Johnson | | 100007 | Ben Zico | | 100008 | Bill Ching | +--------+-----------------+ 8 rows in set (0.004 sec) MariaDB [toyu]> SELECT DISTINCT s.stuId, CONCAT(s.fname, ' ', s.lname) AS student -> FROM student AS s INNER JOIN enroll AS e ON (s.stuId = e.stuId) -> INNER JOIN enroll AS e ON (s.stuId = e.stuId); ERROR 1066 (42000): Not unique table/alias: 'e' MariaDB [toyu]> SELECT DISTINCT s.stuId, CONCAT(s.fname, ' ', s.lname) AS student -> FROM student AS s INNER JOIN enroll AS e1 ON (s.stuId = e1.stuId) -> INNER JOIN enroll AS e2 ON (s.stuId = e2.stuId); +--------+-----------------+ | stuId | student | +--------+-----------------+ | 100000 | Tony Hawk | | 100001 | Mary Hawk | | 100002 | David Hawk | | 100004 | Larry Johnson | | 100005 | Linda Johnson | | 100006 | Lillian Johnson | | 100007 | Ben Zico | | 100008 | Bill Ching | +--------+-----------------+ 8 rows in set (0.002 sec) MariaDB [toyu]> SELECT DISTINCT s.*, e1.*, e2.* -> FROM student AS s INNER JOIN enroll AS e1 ON (s.stuId = e1.stuId) -> INNER JOIN enroll AS e2 ON (s.stuId = e2.stuId); +--------+---------+---------+-------+-------+------+---------+--------+---------+-------+----------+--------+---------+-------+----------+ | stuId | fname | lname | major | minor | ach | advisor | stuId | classId | grade | n_alerts | stuId | classId | grade | n_alerts | +--------+---------+---------+-------+-------+------+---------+--------+---------+-------+----------+--------+---------+-------+----------+ | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10000 | A | 0 | 100000 | 10000 | A | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10000 | A | 0 | 100000 | 10001 | A | 2 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10000 | A | 0 | 100000 | 10002 | B+ | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10000 | A | 0 | 100000 | 10003 | C | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10000 | A | 0 | 100000 | 10004 | A- | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10000 | A | 0 | 100000 | 11001 | D | 4 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10001 | A | 2 | 100000 | 10000 | A | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10001 | A | 2 | 100000 | 10001 | A | 2 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10001 | A | 2 | 100000 | 10002 | B+ | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10001 | A | 2 | 100000 | 10003 | C | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10001 | A | 2 | 100000 | 10004 | A- | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10001 | A | 2 | 100000 | 11001 | D | 4 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10002 | B+ | 1 | 100000 | 10000 | A | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10002 | B+ | 1 | 100000 | 10001 | A | 2 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10002 | B+ | 1 | 100000 | 10002 | B+ | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10002 | B+ | 1 | 100000 | 10003 | C | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10002 | B+ | 1 | 100000 | 10004 | A- | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10002 | B+ | 1 | 100000 | 11001 | D | 4 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10003 | C | 0 | 100000 | 10000 | A | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10003 | C | 0 | 100000 | 10001 | A | 2 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10003 | C | 0 | 100000 | 10002 | B+ | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10003 | C | 0 | 100000 | 10003 | C | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10003 | C | 0 | 100000 | 10004 | A- | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10003 | C | 0 | 100000 | 11001 | D | 4 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10004 | A- | 1 | 100000 | 10000 | A | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10004 | A- | 1 | 100000 | 10001 | A | 2 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10004 | A- | 1 | 100000 | 10002 | B+ | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10004 | A- | 1 | 100000 | 10003 | C | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10004 | A- | 1 | 100000 | 10004 | A- | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 10004 | A- | 1 | 100000 | 11001 | D | 4 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 11001 | D | 4 | 100000 | 10000 | A | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 11001 | D | 4 | 100000 | 10001 | A | 2 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 11001 | D | 4 | 100000 | 10002 | B+ | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 11001 | D | 4 | 100000 | 10003 | C | 0 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 11001 | D | 4 | 100000 | 10004 | A- | 1 | | 100000 | Tony | Hawk | CSCI | CINF | 40 | 1011 | 100000 | 11001 | D | 4 | 100000 | 11001 | D | 4 | | 100001 | Mary | Hawk | CSCI | CINF | 35 | 1011 | 100001 | 10000 | NULL | NULL | 100001 | 10000 | NULL | NULL | | 100001 | Mary | Hawk | CSCI | CINF | 35 | 1011 | 100001 | 10000 | NULL | NULL | 100001 | 10001 | A- | 0 | | 100001 | Mary | Hawk | CSCI | CINF | 35 | 1011 | 100001 | 10001 | A- | 0 | 100001 | 10000 | NULL | NULL | | 100001 | Mary | Hawk | CSCI | CINF | 35 | 1011 | 100001 | 10001 | A- | 0 | 100001 | 10001 | A- | 0 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10000 | B- | 3 | 100002 | 10000 | B- | 3 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10000 | B- | 3 | 100002 | 10002 | B+ | 2 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10000 | B- | 3 | 100002 | 10003 | D | 4 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10002 | B+ | 2 | 100002 | 10000 | B- | 3 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10002 | B+ | 2 | 100002 | 10002 | B+ | 2 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10002 | B+ | 2 | 100002 | 10003 | D | 4 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10003 | D | 4 | 100002 | 10000 | B- | 3 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10003 | D | 4 | 100002 | 10002 | B+ | 2 | | 100002 | David | Hawk | CSCI | ITEC | 66 | 1012 | 100002 | 10003 | D | 4 | 100002 | 10003 | D | 4 | | 100004 | Larry | Johnson | ITEC | NULL | 66 | 1017 | 100004 | 10003 | A | 0 | 100004 | 10003 | A | 0 | | 100004 | Larry | Johnson | ITEC | NULL | 66 | 1017 | 100004 | 10003 | A | 0 | 100004 | 10004 | B+ | NULL | | 100004 | Larry | Johnson | ITEC | NULL | 66 | 1017 | 100004 | 10004 | B+ | NULL | 100004 | 10003 | A | 0 | | 100004 | Larry | Johnson | ITEC | NULL | 66 | 1017 | 100004 | 10004 | B+ | NULL | 100004 | 10004 | B+ | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10003 | NULL | NULL | 100005 | 10003 | NULL | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10003 | NULL | NULL | 100005 | 10004 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10003 | NULL | NULL | 100005 | 10005 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10003 | NULL | NULL | 100005 | 10006 | B+ | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10004 | A- | 0 | 100005 | 10003 | NULL | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10004 | A- | 0 | 100005 | 10004 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10004 | A- | 0 | 100005 | 10005 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10004 | A- | 0 | 100005 | 10006 | B+ | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10005 | A- | 0 | 100005 | 10003 | NULL | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10005 | A- | 0 | 100005 | 10004 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10005 | A- | 0 | 100005 | 10005 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10005 | A- | 0 | 100005 | 10006 | B+ | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10006 | B+ | NULL | 100005 | 10003 | NULL | NULL | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10006 | B+ | NULL | 100005 | 10004 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10006 | B+ | NULL | 100005 | 10005 | A- | 0 | | 100005 | Linda | Johnson | CINF | ENGL | 13 | 1015 | 100005 | 10006 | B+ | NULL | 100005 | 10006 | B+ | NULL | | 100006 | Lillian | Johnson | CINF | ITEC | 18 | 1016 | 100006 | 10004 | C+ | NULL | 100006 | 10004 | C+ | NULL | | 100006 | Lillian | Johnson | CINF | ITEC | 18 | 1016 | 100006 | 10004 | C+ | NULL | 100006 | 10005 | A | NULL | | 100006 | Lillian | Johnson | CINF | ITEC | 18 | 1016 | 100006 | 10005 | A | NULL | 100006 | 10004 | C+ | NULL | | 100006 | Lillian | Johnson | CINF | ITEC | 18 | 1016 | 100006 | 10005 | A | NULL | 100006 | 10005 | A | NULL | | 100007 | Ben | Zico | NULL | NULL | 16 | NULL | 100007 | 10007 | F | 4 | 100007 | 10007 | F | 4 | | 100007 | Ben | Zico | NULL | NULL | 16 | NULL | 100007 | 10007 | F | 4 | 100007 | 10008 | A- | 0 | | 100007 | Ben | Zico | NULL | NULL | 16 | NULL | 100007 | 10008 | A- | 0 | 100007 | 10007 | F | 4 | | 100007 | Ben | Zico | NULL | NULL | 16 | NULL | 100007 | 10008 | A- | 0 | 100007 | 10008 | A- | 0 | | 100008 | Bill | Ching | ARTS | NULL | 90 | NULL | 100008 | 10007 | C- | 0 | 100008 | 10007 | C- | 0 | +--------+---------+---------+-------+-------+------+---------+--------+---------+-------+----------+--------+---------+-------+----------+ 78 rows in set (0.003 sec) MariaDB [toyu]> SELECT DISTINCT s.stuId, CONCAT(s.fname, ' ', s.lname) AS student -> FROM student AS s INNER JOIN enroll AS e1 ON (s.stuId = e1.stuId) -> INNER JOIN enroll AS e2 ON (s.stuId = e2.stuId) -> WHERE e1.classId <> e2.classId; +--------+-----------------+ | stuId | student | +--------+-----------------+ | 100000 | Tony Hawk | | 100001 | Mary Hawk | | 100002 | David Hawk | | 100004 | Larry Johnson | | 100005 | Linda Johnson | | 100006 | Lillian Johnson | | 100007 | Ben Zico | +--------+-----------------+ 7 rows in set (0.001 sec) MariaDB [toyu]> notee