Why do I get an error in log for No matching IF-THEN clause but SAS still able to run correctly

[Nietzsche]

so SAS is able to run an IF statement without THEN statement and this is called subsetting.

But if I follow that with an ELSE statement, SAS is still able run correctly as shown by the code below and the result attached.

data merged nomatch;
	merge cert.patdat (in=inpat rename=(date=BirthDate))
			cert.visit (in=invisit rename=(date=VisitDate));
by id;
if inpat=1 and invisit=1;
else output nomatch;
run;

proc print data=merged;run;
proc print data=nomatch;run;

so why is it that when I look at the log, there is an error No matching IF-THEN clause if everything was ran okay?

[Tom]

I don't see any THEN in your code.

So you have an ELSE without any IF/THEN. Just like the error message says.

Note that a subsetting IF is a completely different statement than and IF/THEN statement.  And there is no way an ELSE statement makes any sense with a subsetting IF.  If the condition is false none of the code after that runs. So the ELSE can never happen.

Click to see corrected code:

Spoiler

data merged nomatch;
  merge cert.patdat (in=inpat rename=(date=BirthDate))
    cert.visit (in=invisit rename=(date=VisitDate))
  ;
  by id;
  if inpat=1 and invisit=1 then output merged;
  else output nomatch;
run;

[Nietzsche]

so SAS still run fine despite the error?

[Tom]

The log will tell you if it ran.

But the logic is wrong so I doubt it did what you wanted if it did run.

[Nietzsche]

no worries, I will stick to IF THEN ELSE standard.

[Kurt_Bremser · Accepted solution]

As the log tells you, no. Syntax errors stop the compilation, so execution never happens.

If you find the resulting dataset, it's from an earlier execution that worked.

[Nietzsche]

omg what a rookie mistake I made.

is there a way to clear the result every time I ran a new code in the same tab in SAS studio?