Data Step Multiple If's

[cellurl]

Where online can i see an explaination of how multiple IF's are handled like below.

Thanks!

   data base(keep =  proposal_nbr tar_file tar_dt the_dt);
      merge base(in=ok1) prop_list(in=ok2);
         by proposal_nbr;
      if ok1;
      if the_dt eq . then the_dt=tar_dt;
      if the_dt lt date()-21;

The first one "gates" if an output is created, so if it misses, the last IF gets a chance to create an output? 

Is that the proper way to look at this?

Also, does it matter that the line "the_dt=tar_dt" isn't higher up in the code?? Does it only take-effect from that point downward?

[ballardw]

The statement IF OK1; is a subsetting if, meaning that output will meet that requirement.

The Order of most statements in the code is very important. In your example the effect of

if the_dt eq . then the_dt=tar_dt;

would not matter as long as it appears between the MERGE (which apparently brings in the values for the variable the_dt) and

the if the_dt lt date()-21; where the newly assigned value would be used.

[cellurl]

so what would this do?

data out;

   set in;

if a;

if b;

if c;

Is this the same as "if a and b and c" then output?

[mohamed_zaki · Accepted solution]

Yes.

You just need to read about  IF Statement, Subsetting, and understand what it is equivalent to.

[mohamed_zaki]

And regarding using "subsetting if" with "Merge" statment and how that work. Check  "ONE-TO-ONE MATCH-MERGE KEEPING SOME OBSERVATIONS " in this paper SAS® DATA Step Merge – A Powerful Tool