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?
The three columns are not independent of each other. The sort is done on the 1st column and then the 2nd column within the sort of the 1st and then the 3rd within the second. You will need to run the sort again by all three columns
