Is there any other way to make tag cloud from mysql without temporary tables?
mysql> explain wallpaper_keywords; +--------------+-----------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------+-----------------------+------+-----+---------+----------------+ | id | mediumint(7) unsigned | NO | PRI | NULL | auto_increment | | wallpaper_id | mediumint(7) unsigned | YES | MUL | NULL | | | keyword_id | smallint(5) unsigned | YES | MUL | NULL | | +--------------+-----------------------+------+-----+---------+----------------+ mysql> explain keywords; +---------+-----------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------+-----------------------+------+-----+---------+----------------+ | id | mediumint(7) unsigned | NO | PRI | NULL | auto_increment | | keyword | varchar(32) | YES | UNI | NULL | | +---------+-----------------------+------+-----+---------+----------------+
SELECT k.keyword,count(k.keyword) AS count FROM keywords k Left Join wallpaper_keywords wk ON wk.keyword_id = k.id GROUP BY wk.keyword_id, k.keyword ORDER BY count DESC limit 100;
+----------+-------+ | keyword | count | +----------+-------+ | computer | 10 | | road | 4 | | tree | 4 | | window | 4 | | nature | 4 | | forest | 3 | | cars | 3 | | mazda | 3 | | abstract | 3 | | funny | 3 | | sport | 3 | | sea | 3 | | city | 3 | | warrior | 2 | | bird | 2 | | lights | 1 | | summer | 1 | | space | 1 | | dusk | 1 | | ubuntu | 1 | +----------+-------+ explain: +----+-------------+--------------------+-------+---------------+---------+---------+------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------------------+-------+---------------+---------+---------+------+------+----------------------------------------------+ | 1 | PRIMARY | keywords | index | NULL | keyword | 99 | NULL | 20 | Using index; Using temporary; Using filesort | | 1 | PRIMARY | | ALL | NULL | NULL | NULL | NULL | 54 | | | 2 | DERIVED | wallpaper_keywords | index | NULL | PRIMARY | 3 | NULL | 54 | | +----+-------------+--------------------+-------+---------------+---------+---------+------+------+----------------------------------------------+ 3 rows in set (0.00 sec)
EDIT
another query:
SELECT count,k.keyword from (SELECT * , count(wk.keyword_id) AS count FROM wallpaper_keywords wk GROUP BY wk.keyword_id LIMIT 50000) as data left join keywords as k on k.id = data.keyword_id order by count desc limit 500
+----+-------------+------------+--------+---------------+------------+---------+-----------------+------+----------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+--------+---------------+------------+---------+-----------------+------+----------------+ | 1 | PRIMARY | | ALL | NULL | NULL | NULL | NULL | 20 | Using filesort | | 1 | PRIMARY | k | eq_ref | PRIMARY | PRIMARY | 3 | data.keyword_id | 1 | | | 2 | DERIVED | wk | index | NULL | keyword_id | 3 | NULL | 59 | | +----+-------------+------------+--------+---------------+------------+---------+-----------------+------+----------------+
the question would be now – is there any better solution? cheaper (SHOW STATUS LIKE ‘last_query_cost’;) way to count it?
For counting total value for every keyword you cau use additional field (total_count) in table keywords and by every adding new keyword add +1 to this field – it’s really simpler for your database in future, when you will have 100 000 records.