On 8/27/07, Simetrical Simetrical+wikilist@gmail.com wrote:
mysql> EXPLAIN SELECT * FROM user WHERE user_name='Simetrical' AND SUBSTRING(user_password, 1, 1) BETWEEN '8' AND 'f'; +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+ | 1 | SIMPLE | user | const | user_name | user_name | 257 | const | 1 | | +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+ 1 row in set (0.00 sec)
mysql> EXPLAIN SELECT * FROM user WHERE user_name='Simetrical' AND SUBSTRING(user_password, 1, 1) BETWEEN '8' AND 'f'; +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+ | 1 | SIMPLE | user | const | user_name | user_name | 257 | const | 1 | | +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+ 1 row in set (0.00 sec)
That first one should, of course, be:
mysql> EXPLAIN SELECT * FROM user WHERE user_name='Simetrical' AND SUBSTRING(user_password, 1, 1) BETWEEN '0' AND '7';+----+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+ | 1 | SIMPLE | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE noticed after reading const tables | +----+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+ 1 row in set (0.00 sec)