how can I make a field that I want pick in sql statement generic. For example I can write the following sql statements

select firstname from testdata into cursor test where firstname == a
select lastname from testdata into cursor test where lastname == b
select address from testdata into cursor test where address == c

how can I make it so that the selection fields can substituted with a variable? for example

select fieldname from testdata into cursor test where fieldname == somevariable

I want to be able to choose my own fieldnames.

Thanks
Nick Patel