Create a table like this: CREATE TABLE itg_passwd ( Username char(20) NOT NULL default '', Password char(20) NOT NULL default '', PRIMARY KEY (Username), KEY zzzz (Password(4)) ) TYPE=MyISAM;
And insert some data; insert into itg_passwd values('1','h1'), ('2','h2'), ('3','h1/a'); Then Query index of itg_passwd: show index from itg_passwd; I can see Cardinality of index zzzz is 'NULL' ! (It should be 3) Why??? --------------------------------------------------------------------- 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