IF STATEMENT TO CREATE MACRO VARIABLE

I am attempting to create a macro variable based on the value contained in an outside table. I'm currently using this:

PROC SQL NOPRINT;
SELECT compress("'" || put(MAX(CALL_DATE)+1 , DATE9.)|| "'")
into :start_date 
FROM table.test
;

This provides me the max date from my table as '10OCT2018' The problem is that when I initially run this my source table will not have a max value as it will be blank so it evaluates to '.' I'd like to do something like:

PROC SQL NOPRINT;
SELECT IF compress("'" || put(MAX(CALL_DATE)+1 , DATE9.)|| "'") ='.' THEN 
'10OCT2018' ELSE compress("'" || put(MAX(CALL_DATE)+1 , DATE9.)|| "'") END
into :start_date 
FROM table.test
;

This would allow me to fill the variable when the source table is empty but then make use of the max date after it has been updated with data.