How to update new data and avoid duplicates

[co_ba]

What is the best approach to update a data set that only adds the new data, change in case of revisions but does not create a duplicate variables?

data merge, proc sql?

Thanks for your advice

co-ba

[Tom]

If you want to replace existing rows then use MERGE. Make sure to have the new dataset listed last.

data want ;

   merge old new ;

   by id ;

run;

You could also look at the UPDATE statement, but that is really intended for transactions, not new records.  Read about what happens when the transaction dataset has missing values for a variable.

For more complicated situations look at the MODIFY statement.

[Ksharp]

What is your sample data?

What data do you want to add ? and Final dataset is what looks like?

Ksharp