MySQL在id字段上按x字符组

I have a client database that is in a pretty poor state, but I have to work with it. We have a set of product id's and each id is made up of the attributes of the product. What i'd like to do is select those id's that match the first 4 or 5 characters and have them in a drop down box as variants of a selected product.I have a client database that is in a pretty po