Difference between &A and &A.

[astha8882000]

I'm looking at a piece of code given below, this is just a small part of a really big project. But I'm unable to understand a concept here:

Proc sql noprint;

      Select max(count) into:A

            From ABC;

quit;

DATA _NULL_;

      IF &A. < 1 THEN

            DO;

            [some code]

END;

Here, A is a macro variable as provided in the proc sql statements, then instead of referencing it as &A in the data step, why is this being referred to as &A.. Why is there a period added while referencing it?

[novinosrin]

Why is there a period added while referencing it?

Test the same code without the period as suffix

[Astounding]

The period is optional when referring to a macro variable.  It doesn't matter if  you use it here or not.

It comes in handy when the name of the macro variable is ambiguous.  For example:

&ABC

Is this the macro variable &A followed by the letters "BC"  or is it the macro variable &ABC?  For the macro variable &A followed by the letters "BC" you would clarify that by using:

&A.BC

[astha8882000]

ABC is a table and A is just a variable that  is obtaining some value from that table.

[Astounding]

OK, I think you need a few examples to clarify then.  Try running this code:

%let a=1;

%let ab=2;

%let abc=3;

%put abc;

%put &abc;

%put &abc.;

%put &a.bc;

%put &ab.c;