Date function problems with dates from core not recognized as dates

Question

Our core provides dates in two formats: YYYYDDD and MMDDYY (YYYYDDD for today [2/21/12] would be 2012052).  We have determined that Crystal Reports is not viewing them as dates, but rather numbers. If querying on just a specific date, no problem. But if I want to use a date function like DayOfWeek, then things don't work.
I need a report to always provide yesterday's data - except on Monday, where it needs to look back at Friday.
I tried a criteria of:
if DayOfWeek(CurrentDate) = 1 then {DDMAST.DATOP7} = CurrentDate - 2 else
if DayOfWeek(CurrentDate) = 2 then {DDMAST.DATOP7} = CurrentDate - 3 else
{DDMAST.DATOP7} = CurrentDate -1
{DDMAST.DATOP7} is the date field from our core.
I tried this but got an error message of "A Number is Required Here" and it highlights the CurrentDate - 2.
Since we believe that Crystal Report is not viewing our dates as dates - but viewing them as numbers, what do I need to do to correct this?  Someone suggested I'd need to extract each date portion (month, date, and year) and create variables to "build" a date that Crystal Reports would understand.  Any suggestions?

Answer 1

Hi, 
You're correct.  There appears to be two branches in this thread. 
To address your issue, Crystal only recognizes actual date types, ie. Months, Days and Years.  Your serial date isn't a recognized date type so we have to: 
1)  Determine which format your date field is
2)  Convert your number to a date using the appropriate formatting. 
I am assuming your dates will either be 6 (MMddyy) or 7 (yyyyddd) characters long.  If there are other patterns you'll need to determine that. 
The problem I found is what does your date for today (March 6, 2012) look like in MMddyy format? 
Any month before October would never have a leading 0 if your date is stored as a number.  So you should take that into account as well using my logic. 
I added that into the logic by checking for a length of 5. 
NumberVar Full := 030612;
StringVar myDate;
myDate := ToText (Full, 0, "", "");
Select Length (myDate)
    Case 5: Date (2000 + ToNumber (myDate [4 to 5]), ToNumber (myDate [1]), ToNumber (myDate [2 to 3]))
    Case 6: Date (2000 + ToNumber (myDate [5 to 6]), ToNumber (myDate [1 to 2]), ToNumber (myDate [3 to 4]))
    Case 7: Date (ToNumber (myDate[1 to 4]), 1, 1) + (ToNumber (myDate [5 to 7]) - 1)
    Default: Date (0, 0, 0);
If you edit the first line and change it to: 
NumberVar Full := 2012066;
You will also get today's date.