Given the following table: CREATE TABLE campaign_t ( acct_id int(11) unsigned NOT NULL default '0', site_id tinyint(3) unsigned NOT NULL default '0', ref_id int(11) unsigned NOT NULL default '0', datestamp char(10) NOT NULL default '', raws int(11) unsigned NOT NULL default '0', uniques int(11) unsigned NOT NULL default '0', trial_signups int(11) NOT NULL default '0', full_signups int(11) NOT NULL default '0', annual_signups int(11) unsigned NOT NULL default '0', PRIMARY KEY (acct_id,site_id,ref_id,datestamp), KEY acct_id (acct_id), KEY site_id (site_id), KEY ref_id (ref_id), KEY datestamp (datestamp) ) TYPE=MyISAM;
How come it doesn't use the 'datestamp' index on this query: mysql> explain SELECT * FROM campaign_t WHERE datestamp < 20041105\g +------------+------+---------------+------+---------+------+--------+------------+ | table | type | possible_keys | key | key_len | ref | rows | Extra | +------------+------+---------------+------+---------+------+--------+------------+ | campaign_t | ALL | datestamp | NULL | NULL | NULL | 438166 | where used | +------------+------+---------------+------+---------+------+--------+------------+ 1 row in set (0.00 sec) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
