Timing in mysql using php

[Albert Chang]

few questions... in php how do i do the followings?

i have a table that has many categories... I want to reset one of the columns to zero at 12:00am every friday automatically. How do I do that?

Second, i have a column thats auto_increment... lets say i set the first value to 10... if i add one more row... then the next row will be 11... how do i reset it to start with 0? thank you!