Sorting an almost sorted dataset in SAS?
I have a large dataset in SAS which I know is almost sorted; I know the first and second levels are sorted, but the third level is not. Furthermore, the first and second levels contain a large number of distinct values and so it is even less desirable to sort the first two columns again when I know it is already in the correct order. An example of the data is shown below: <pre> ID Label Frequency 1 Jon 20 1 John 5 2 Mathieu 2 2 Mathhew 7 2 Matt 5 3 Nat 1 3 Natalie 4 </pre> Using the "presorted" option on a proc sort seems to only check if the data is sorted on every key, otherwise it does a full sort of the data. Is there any way to tell SAS that the first two columns are already sorted?