Mega Code Archive
GROUP BY WITH ROLLUP
<![CDATA[
mysql>
If GROUP BY groups only a single column, then WITH ROLLUP simply has the effect that an additional sum row is
added
mysql>
mysql>
mysql> CREATE TABLE titles (
-> titleID int(11),
-> title varchar(100),
-> subtitle varchar(100),
-> edition tinyint(4),
-> publID int(11),
-> catID int(11),
-> langID int(11),
-> year int(11),
-> isbn varchar(20),
-> comment varchar(255),
-> ts timestamp,
-> authors varchar(255),
-> PRIMARY KEY (titleID)
-> );
Query OK, 0 rows affected (0.01 sec)
mysql>
mysql>
mysql>
mysql> INSERT INTO titles VALUES (1,'Linux','Installation',5,1,57,2,2000,NULL,NULL,'2005-02-28 13:34:21','Michael'),
-> (2,'Excel',NULL,NULL,2,3,NULL,2000,NULL,NULL,'2005-02-28 13:34:22','David'),
-> (3,'XML',NULL,NULL,1,2,NULL,1997,NULL,NULL,'2005-02-28 13:34:22','Edwards'),
-> (4,'PHP',NULL,NULL,3,6,NULL,2000,NULL,NULL,'2005-02-28 13:34:22','Tom'),
-> (5,'MySQL','',0,3,34,NULL,2000,'','','2005-02-28 13:34:22','Paul'),
-> (6,'Java',NULL,NULL,4,34,NULL,1999,NULL,NULL,'2005-02-28 13:34:22','Tim');
Query OK, 6 rows affected (0.00 sec)
Records: 6 Duplicates: 0 Warnings: 0
mysql>
mysql>
mysql>
mysql> CREATE TABLE languages (
-> langID int(11) NOT NULL auto_increment PRIMARY KEY,
-> langName varchar(40),
-> ts timestamp
-> );
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
mysql>
mysql> INSERT INTO languages VALUES (1,'english','2004-12-02 18:37:02'),
-> (2,'deutsch','2004-12-02 18:37:02'),
-> (3,'svensk','2004-12-02 18:37:02'),
-> (4,'norsk','2004-12-02 18:37:02');
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql>
mysql>
mysql> SELECT langName, COUNT(*)
-> FROM titles, languages
-> WHERE titles.langID = languages.langID
-> GROUP BY langName WITH ROLLUP;
+----------+----------+
| langName | COUNT(*) |
+----------+----------+
| deutsch | 1 |
| NULL | 1 |
+----------+----------+
2 rows in set (0.00 sec)
mysql>
mysql> drop table titles;
Query OK, 0 rows affected (0.00 sec)
mysql> drop table languages;
Query OK, 0 rows affected (0.00 sec)
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