Passing parameter into select statement by using function in discoverer

Question

I have created two functions in database named Period_in and Period_out and a global variable  g_period_name
I have called Period_out function in VIEW(Select statement where condition).
I have registered Period_in function in discoverer admin then created calculation (called Period_in(:input parameter))in discoverer plus.
My expectation is user will enter period name and that will hit Period_in function and returns 1 and stores entered period name in g_period_name at runtime. then VIEW will executed and fetches data.
But i am getting no data found.
Problem is 2 functions running at the same time in select statement. Please help me to overcome this. Thanks in advance
FUNCTION period_in (p_period VARCHAR2)
      RETURN NUMBER
   AS
   BEGIN
      g_period_name := p_period;
      RETURN 1;
   END period_in;
   FUNCTION period_out
      RETURN VARCHAR2
   AS
   BEGIN
      RETURN g_period_name;
   END period_out;

Answer 1

You can use this code: 
WITH cte
AS ( SELECT EmpID ,
EmpName ,
[dbo].[udf_testFunction](EmpID) AS testfunctionvalue
FROM #Temp
SELECT EmpID ,
EmpName ,
testfunctionvalue ,
testfunctionvalue * EmpID ,
testfunctionvalue + 2
FROM cte
But using scalar functions in select clause can hurt the performance. Please see this link: 
SQL Server Scalar User Defined Function Performance
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