APEX

I need help building a dynamic where clause in 1.6

I have three fields:
p1_col_where which is a static list of 8 columns
p1_condition which is a static list of the 9 possible conditions(=,<,>...)
p1_condition_value is a text field that the user enters the literal they want to use

The lov select I thought would be:
SELECT Description, positem
FROM v_item
WHERE :P1_COL_WHERE :P1_CONDITION :P1_CONDITION_VALUE

I was hoping that this would be resolved to: WHERE item = 123
but of course I get a big NASTY error.

Can someone help me out?

Thanks,
Joe