The IF/THEN/ELSE construct is used for conditional execution of DGL statements.
In this statement, the statements following the THEN (and before any ELSE) are executed if the boolean_expression evaluates to true. If it is evaluated to false, the statements following the ELSE are executed, when present.
IF a >= b THEN
EXECUTE (’DATE’) ;
INCLUDE (’sample.txt’) ;
ELSE
WRITE (’a is less than b’) ;
END IF ;