Writing formulas selecting fixed denominator

[dunken]

Id like to write a formula ("@NoxDiff&quot that select NOx from each year after 1995 and divide it with NOx from 1995. My table include among others following values;
Town, Year, NOx, SO2, H+
Stockholm, 1995, 400,
Stockholm, 1996, 360
Stockholm, 1997, 355
Stockholm, 1998, 353
Stockholm, 1999, 255
Stockholm, 2000, 274
Malmo, 1995, 350
Malmo, 1996, 370
Malmo, 1996,

How shall i write it?
The resulting table would include the following indexes;
Town, Year, I(NOx)
Stockholm, 1996, 0.9
Stockholm, 1997, 0.8875
Stockholm, 1998, 0.8825
....
I have CP ver 9.
Please I´ve spent two days testing different formulas - I have small experiense from programming..

 

[dgillz]

Use a variable to do this.

In the group header to reset the variable by city:
WhilePrintingRecords;
Numbervar Demon:=0

In the details section to calculate the demoninator:
WhilePrintingRecords;
Numbervar Denom;
If {year}=1995 then Numbervar Denom:={AmountField} else Denom

In the details section to calculate the percentage:
WhilePrintingRecords;
{AmountField}/Numbervar Base

Software Sales, Training, Implementation and Support for Exact Macola, eSynergy, and Crystal Reports

http://www.trianglepartners.com

 

[dunken]

OK Thanks - fast service!!!
It doesnt work => Can U se wats wrong

///Im going to put the formula into Cross tabs for each city => do you think I must have this part? If so - Will it be in the same formula?
//In the group header to reset the variable by city:
//WhilePrintingRecords;
//Numbervar Demon:=0

//In the details section to calculate the denominator:
WhilePrintingRecords;
Numbervar Denom;
If {arsdata_.year}=1995 then Numbervar Denom:={arsdata_.NOx} else Denom

//the details section to calculate the percentage:
/// Isnt somethíng missing here? - The declaration of Base?
WhilePrintingRecords;
{arsdata_.NOx}/Numbervar Base

 

[dgillz]

I do not recommend using a cross tab for this. Just use a regular report with a group by city. I am unsure how a crosstab will affect this formula.

On the last formula, I don't know where my head was, it should read as follows:

WhilePrintingRecords;
{AmountField}/Numbervar Denom

Software Sales, Training, Implementation and Support for Exact Macola, eSynergy, and Crystal Reports

http://www.trianglepartners.com

 

[Naith]

You also want to check that all your variables are called Denom as opposed to Demon as above.

Naith