best way to sum values in a variable with a large dataset

[pinkyc]

I have input data like this:

Pat_ID     Discharge_Date     Paid

AA                                           55.00

AA                                            0.00

AA          01/01/2012             -180.00

AA          04/01/2012             44.00

AA                                             37.00

AA                                             54.00

AA                                             0.00

BB                                             -200

BB          09/23/2012                   0.00

BB                                                54.00

I need to sum Paid by two ways, just grouping by Pat_ID and alternately by Discharge_Date and Pat_ID (so only the ones with not blank discharge dates are summed).  I know I can just create a sub-table with If Discharge_Date NE '' and sum the remaining Pat_ID's but was wondering if there's a way to do it in one step, more or less?  I also have 1580312 observations so I wonder if a proc sql method is better than the data step and sum.

[Reeza]

I would recommend proc means/univariate/summary, especially since you can calculate sub-totals without an additional step.

Look into the CLASS, WAYS and TYPE statement in proc means.

[ballardw · Accepted solution]

I agree with Reeza. With an output data set from proc summary there will be a variable _type_ that describes the combinations of the class variables.

Proc summary data=have;

     class Pat_id Discharge_date;

     var paid;

     output out=want sum=;

run;

for example.

By default you well get a sum for 1) all records 2) each Pat_id 3) each Discharge_date and 4) each unique combination of Pat_id and Discharge_date.