I found the solution!
Stringvar Array strings := Split({?empNoList}, "_"); //Spliting and saving the string in a string array
Numbervar Array numbers; //Creating a number array
Redim numbers[Ubound(strings)]; //Declaring number array size
Numbervar i;
//For loop to traverse through string and convert each into numbers and saving them in the numbers array
for i := 1 to Ubound(strings) do (
numbers[i] := ToNumber(strings[i]);
);
if({EMP_LEAVE_REPORT_VIEW.EMP_NO} in numbers) //If condition to check whether Employee number is in the numbers array
then
(true;)
else (false;)
It was a simple out of the box thinking ;)