Using Data Step how to update a Data Set based on comparison with another Data Set?

[manojsanthi]

Hello,

I am new to SAS and to SAS Data Step. I want to know how I can update a Variable V1 in a Data Set A with the Value "Yes" whenever there is a match with Data Set B having a common Variable V2 between the 2 data sets?

[Reeza]

Depends on your data structure, but you can try a MERGE or UPDATE statement or MODIFY as starters.

[manojsanthi]

I read about Merge and Update, but I don't see how it can benefit my specific query as I am looking to enter a Constant String value in a Variable when ever there is a match in Values between 2 tables.

[Reeza]

Show an example of why you think it won't work.

[Astounding]

You're looking in the right direction.  You need to add to what you have seen so far by adding IN= variables when you MERGE.  For example:

data want;
   merge a (in=from_a) b (in=from_b);
   by V2;
   if from_a;
   if from_b then v1='Yes';
run;

This example assumes that both data sets are already in sortedf order by V2.