if-then and parameterized where clause

[Jeronimo]

I'm learning Crystal Reports v8, and am fixing some 55 old reports. The reports currently offer results based on a date, but now we want to have a range as well as being able to see a result set showing those records with null dates (which would be unposted transactions).

I can do it with a straight SQL query, and thus could build a stored procedure to use the parameters (which come from another source); I don't want to have to build 55 stored procedures to handle this problem, and I would prefer to handle it within the formula builder if I can.

I've tried setting the formula, but Crystal Reports doesn't seem to want to respect more than one set of parentheses, so my where clause ends up being too inclusive; using the if-then structure seems to knock out the where clause entirely, so ALL the data comes back for the report to weed through.

Basically I would like to be able to put a complicated where clause in the formula builder .. here's an example, and TIA.

{tblA.tType} = "S" and
{tblA.Place} = {?syslace} and
(({?sys:jDays} < 0) and (IsNull({tblA.Posted}))) or
(({?sys:jDays} > -1) and ({tblA.Posted} in ({?sys:jDate} - {?sys:jDays}) to {?sys:jDate}))

I would like the where clause to come out as follows: if the passed variable jDays is <0, then

WHERE
(tblA.tType = 'S' AND
tblA.Place = 211 AND
tblA.Posted >= '2001-05-08' and
tblA.Posted <= '2001-05-09')

otherwise

WHERE
(tblA.tType = 'S' AND
tblA.Place = 211 AND
tblA.Posted is null)