retrieve data in datalist from DB based on Checkboxlist Item

Question

hello,

 

My Question is

 

how to retrieve data from database in datalist based on checkboxlist values. like filters use in ecommerce. for ex. i have a checkbox list it has priorities for questions. hard , easy , important. when user check on hard all hard questions show in datalist. when check hard and easy both, then both priority question show in datalist, then if he/she uncheck one item . then remaining checked priority questions still show in datalist. its urgent.?