calculating the difference between two rows

[deleted_user]

Hi,
i'm trying to calculate the difference between two observations from the same variable on two differents rows. Per example,
id var
1 4
1 2

Basically, making 4-2.

Thanks,

JS

[deleted_user]

Lag function may be an option.

http://support.sas.com/ctx/samples/index.jsp?sid=1498&tab=code