I have a online store and here is my probelm:

I need to have product details stored in the DB and pulled into the product decriptions as needed.
Some products need them and some don't, and the ones that do may or may not need all of the feilds so I only want it the add it to the product decscripion if there is info but not give me a bunch of empty fields fo the ones that dont.

Either you use 2 diffrent tables - or you just deal with the empty fields in a diffrent way:
<?php
if ( field_data == "" ) {
?>
<!-- Empty field --!>
HTML here

<?php
}
if ( field_data != "" ) {
?>
<!-- Not Empty field --!>
HTML here
<?php
}