Union distinct records from multiple datasets

[Reeza]

Make sure you're deleting the final data set between run iterations.
I don't see what's generating that error, does the FINAL data set have what you want?

Another approach would be to to create 100's of summary data sets and just stack them all at the end but I usually don't like leaving datasets around like that personally, I find it messy. If you'd like to try that approach, remove the APPEND and PROC DATASETS, and give each output a unique name, same prefix, in the last data step. Then append them all together using the colon shortcut method.