About index in my sql

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 (Password(4)) ) TYPE=MyISAM; And insert some data; insert into itg_passwd values('1','h1'), ('2','h2'), ('3','h1/a'); Then

About index in my sql!

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 (Password(4)) ) TYPE=MyISAM; And insert some data; insert into itg_passwd values('1','h1'), ('2','h2'), ('3','h1/a'); Then