First differences with proc sql?

[Maria57]

Hi

So i have data for sales for two years for different companies:

Company_code Sales  Year

1                          5       01

1                          25     05

2                          150   01

2                          75     05

4                          1       01

4                          9       05

etc.

I now would like to create a dataset with the change in sales from year, such as:

Company_code DiffSales

1                      20

2                      -75

4                      8

Is it possible to do this with proc sql? I am new to SAS, so help is much appreciated.

Thanks

[DBailey · Accepted solution]

assuming you only have two years of data and each company has two years;;;

proc sql;

create table want as

select

     t1.company_code,

     t2.sales - t1.sales as diffSales

from

     have t1

     inner join have t2

          on t1.company = t2.company

          and t1.year <> t2.year

where

     t1.year='01';

quit;

[Maria57]

Thanks!