>> I have a table, around 320 fields... <<
You might want to read the SQL standards, so you'd know what the term "field" means in this language. It is a meaningful subset of values in a column, such as year, month and day fields in a column of DATE type. I would assume you probably misspoke. And you really meant 320 columns, each modeling a particular attribute with a particular data type.. But I'm curious as to what these columns mean. In over 30 years, I have only gone a little over 100 columns; the example was an individual allergy tests laid out in a grid taped off on the back of a patient. Any other time I've seen something this big. It's been a denormalized mess, or someone tried to put an entire dossier into one table without normalizing it. Could you give us a little more information?
Please post DDL and follow ANSI/ISO standards when asking for help.