jwcolby
jwcolby at colbyconsulting.com
Sat Mar 19 08:55:51 CDT 2011
I got into the hashing business in order to create a surrogate key of sorts, in fact a trio of them. I have an address hash, a family hash and a person hash. I compute these three hashes for every table of persons. Now that I have these surrogate keys I have "identical" values in a single field where the input is identical in multiple fields. Thus I do not have to do multi-field joins where I have a hash for all of those fields. I am happy to hear that I am secure in my surrogate hash algorithm choice. OK, so I have these hashes. Every record has these three hashes. Now some definitions: HashAddr: A unique address is addr/zip5/zip4 different HashFamily: A unique family is LName/Addr/Zip5/Zip4 different HahsPerson: A unique person is FName/LName/Addr/Zip5/Zip4 different. Using this information, I need to calculate the count of addresses with a single person, with two persons etc for as many combinations as I have. Addresses People 22,538,240 1 780,462,346 2 52,234 3 people etc etc till every quantity of people is found. What is the simplest way to accomplish this with SQL. -- John W. Colby www.ColbyConsulting.com