The Or operator is not working

Question

I have Crystal Reports XI, and I can't get the Or operator to work in the record selection formula.  I can get each individual line to work, but once I put an Or statement in, nothing shows up in my report.
{CP_ORDLIN.QTY_BO} > 0 Or
{CP_ORDHDR.CODE_STAT_ORD} <> "Q"
Each line works individually, but once I put the Or operator between them, I get nothing.

Answer 1

Hello Rob,
Steve's original question concerned the selection filter:
{CP_ORDLIN.QTY_BO} > 0 OR {CP_ORDHDR.CODE_STAT_ORD} = "Q"
However, Steve's subsequent post has a Where clause:
"CP_ORDHDR"."CODE_STAT_ORD"'Q' AND "CP_ORDLIN"."SEQ_LINE_ORD"=10 OR "CP_ORDLIN"."QTY_BO">0
The latter statement is more restrictive than the former, since the AND operator takes precedence over OR.  For example:
False AND True OR False == (False AND True) OR False == False OR False == False
Boolean algebra is distributive, so
a AND b OR c == (a AND b) Or c == (a OR c) AND (b OR c)
so the second expression above becomes
("CP_ORDHDR"."CODE_STAT_ORD"'Q' OR "CP_ORDLIN"."QTY_BO">0) AND ("CP_ORDLIN"."SEQ_LINE_ORD"=10 OR "CP_ORDLIN"."QTY_BO">0)
(so I used to do this for a living once...)
Since the expression Steve originally asked about was different from the SQL, I wanted to know where the additional AND clause had come from.
Sincerely,
Ted Ueda
ps.  Graham's referring to [Short-Circuit Evaluation|http://en.wikipedia.org/wiki/Short-circuit_evaluation] that Crystal supports.  This is useful if you want to evaluate a condition such as:
(1 / {?x} > 10)
which is problematic if there's a possibility that {?x} can be zero, since that would raise a divide by zero exception.  So you'd write:
({?x} = 0) OR (1/{?x} > 10)
and that's safe, since if {?x} is zero, the right-hand size of the OR would be True and the left-hand size won't have to be evaluated.
This is equivalent to:
If {?x} = 0 Then
    True
Else If (1/{?x} > 0) Then
    True
Else
    False