How Do I Extra records this way

[TakumaHabu]

i want to extra all the records which say the "username" field stars with letter A and B C etc. How would I do that without reading all the records as I have 10000 users and itll just take too much to read all the users...

Thanks

[devinemke]

for the A's...

SELECT * FROM table WHERE username LIKE 'a%'