Hello I think the gruop by is behaving strange. Could someone please explain this or maybe point me to a definition of the group by. (Inspired by http://www.mysql.org/doc/E/x/Examples.html).
CREATE TABLE shop ( article INT(4) UNSIGNED ZEROFILL DEFAULT '0000' NOT NULL, dealer CHAR(20) DEFAULT '' NOT NULL, price DOUBLE(16,2) DEFAULT '0.00' NOT NULL, PRIMARY KEY(article, dealer)); INSERT INTO shop VALUES (1,'A',3.45),(1,'B',3.99),(2,'A',10.99),(3,'B',1.45),(3,'C',1.69), (3,'D',1.25),(4,'D',19.95); mysql> SELECT * FROM shop; +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0001 | A | 3.45 | | 0001 | B | 3.99 | | 0002 | A | 10.99 | | 0003 | B | 1.45 | | 0003 | C | 1.69 | | 0003 | D | 1.25 | | 0004 | D | 19.95 | +---------+--------+-------+ 7 rows in set (0.00 sec) mysql> select * from shop GROUP BY article; +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0001 | A | 3.45 | | 0002 | A | 10.99 | | 0003 | B | 1.45 | | 0004 | D | 19.95 | +---------+--------+-------+ 4 rows in set (0.00 sec) QUESTION: I had expected 7 rows - where did the rest go? mysql> select * from shop GROUP BY article having price=max(price); +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0002 | A | 10.99 | | 0004 | D | 19.95 | +---------+--------+-------+ 2 rows in set (0.00 sec) QUESTION: I had expected 4 rows (one for each article) - where did the rest go? mysql> select * from shop GROUP BY article having price=min(price); +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0001 | A | 3.45 | | 0002 | A | 10.99 | | 0004 | D | 19.95 | +---------+--------+-------+ 3 rows in set (0.00 sec) QUESTION: It seems like group by only return the first row in the group - is this correct? I am not trying to solve a specifik problem - I would just like to know how the group by works in MySQL. T2K --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
