GROUP BY WITH ROLLUP : ROLLUP « Select Clause « SQL / MySQL

1. SQL / MySQL
2. Select Clause
3. ROLLUP

GROUP BY WITH ROLLUP

     
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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