field is unknown. it is neither in one of specified tables nor defined by data statement

Hello,

I'm doing enhancement  to filter the data for the input parameters. Also I've coded implicit enhancement for the selection parameters to be displayed on standard IE05 selection screen.

Defined a block as follows in standard  program RIHEQUI20

selection selectio begin of block b1 with frame title text-099.

select-options:

                    cre_date for equi-zzcreate_date,

                    lp_pdate for equi-zzprint_date.

selection selectio end of block b1.

now to filter the data corresponding to the input in selection parameters i've explicit enhancement point in which added coded in where condition

as

zzcreate_date IN cre_date

AND zzprint_date IN lp_pdate

but error message showing the above heading

...

Solution for that....PLZ help!!