Read Sequentially and Calculate

Question

Hello,
I am running into the following situation I am trying to handle in Crystal Reports and am looking for input...
Datasource1:  orders
Datasource2:  unit of measure conversion formulas
In Datasource1 the order quantities are in a specific unit of measure... ie CASE packages (boxes)
The user will request (in a parameter) to list the order quantites in EACH unit of measure
In Datasource2 we may find the following conversion formulas...
     PACK  to EACH, multiply PACK qty by 2 to get EACH value
     CASE to PACK, multiply CASE qty by 30 to get PACK value
In some situations, there is not a direct formula to convert CASE on the order to EACH as the user requested.
I have the report created to pull from Datasource1 and Datasource2 in one SQL Command (in Crystal)
and it works if there is a direct conversion formula found in Datasource2.
If the Conversion quantity is blank on the report, no formula conversion found, I need to read through the conversion formulas
that are there to come up with a value to convert from CASE to EACH.
I created a subreport within the main report that does list out all of the conversion formulas found for the item, but
need to know how to pass Quantity value into the subreport and pass Quantity value back out...  and also need to
keep track of conversion formula records found in the subreport to see if I can come up with a conversion value to pass back.
can the above be done ?
if not, is there a better way to do this ?
Thanks

Answer 1

What you're trying to do isn't going to work directly in CR. You'll need to do it in the SQL.
As it stands, you may be able to write a WHILE loop to bring everything together but it would be unnecessarily complex.
Your best option(s) is to either 1) finish filling out all of the possible permutations in table 2 or 2) redesign table 2 so that each unit of measure is expressed as a multiple of the smallest possible unit.
example:
Unit________ Quantity
Each_______ 1
Pack_______ 2
Case_______60
so...
Pack to Each  = 2 / 1 = 2
Case to Pack = 60 / 2 = 30
Case to Each = 60 / 1 = 60
Each to Pack = 1 / 2= 0.5
Obviously 2) is the better choice but if you aren't in a position to alter the DDL of table 2, option 1) will work, it will just take more effort.
HTH,
Jason