Parameter Default dates and user Dates issue

[JSMITH242B]

Hi All,
I have 2 parameters DateStart and DateEnd.
I have set defaults for these: DateStart 01/04/2005 and DateEnd 31/12/2009.
However the user has the option to enter in their own dates.
I have used the following formulae but it is not returning the correct records.
Any ideas?
({Purchase_Requests.Open Date & Time} IN {?DateStart} TO {?DateEnd} OR ({?DateStart} >= date('01/04/2005') and {?DateEnd} <= DATE('31/12/2099')))

Your help is much appreciated.

 

[lbass]

Try something like:

(
if {?DateStart} <> date(2005,04,01) then
{table.date} >= {?DateStart} else
{table.date} >= date(2005,04,01)
) and
(
if {?DateEnd} <> date(2099,12,31) then
{table.date} <= {?DateEnd} else
{table.date} <= date(2099,12,31)
)

-LB