closest string matching

Hi,

I have a model number in one table like 'Q4SD-X24K' and i have a model number in another table like 'q4%' and 'q4sa%d' and q4sd%' and each one contains different pdf links.

and if the user searches for 'Q4SD-X24K' , the closest match i.e q4sd will come and q4sd.pdf has to assign and show up .

and i have written one stored proc and i am getting data in a datatable q4,q4sa%d,q4sd in asp.net. how can i match the closest one from this datatable to model number?