Error when substracting 2 dates in Packgage using toad

Question

Hi there , I am having a problem when calculating dates in a package usiong Toad.
I have my function :
FUNCTION PORTFOLIO_MEMO_RPT_Sql
( schema_name IN  VARCHAR2
  , select_business_date IN  DATE
) RETURN VARCHAR2
SELECT DISTINCT
       Case
    when NVL(TO_DATE(''09/24/2013'',''MM/DD/YYYY'') - DECODE(mn.Active, 1, mn.DueDate, sc.DueDate ),0) = 0 then ''0Days''
    when NVL(''' || select_business_date  || '''   - DECODE(mn.Active, 1, mn.DueDate, sc.DueDate ),0) = 0 then .....
when I give it my variable from outside , it is not working......but when I use a date inside, it works.
Please note I call my function from outside like :
SELECT * FROM  TABLE ( FI_rpt.Fi_Rpt_Pkg_loan.PORTFOLIO_MEMO_RPT (sys_context('userenv','session_user'),TO_DATE('09/24/2013','MM/DD/YYYY')) ) 
Any help ?

Answer 1

Hi,
Once again, post a complete test script that people can run to re-create the problem.
The script just has to show the problem you need to solve.  If it's difficult to post the acutal tables that get the actaul results you need, then post something simpler that just shows the part you don;'t understand.
It looks like the part you don't understand is: "How can I create dynamic SQL with a DATE datatype?"
For example, say you need a function that takes 2 arguments: a table name and a DATE (cutoff_date), and it returns the number of rows in that table where hiredate>=cutoff_date.  That is, given the scott.emp table, we'd like to write a query such as this:
SELECT    ename, hiredate
,         hired_since ('SCOTT.EMP', hiredate)  AS h
,         hired_since ('SCOTT.EMP', SYSDATE)   AS t
FROM      scott.emp
ORDER BY  hiredate;
and have it produce resutls like this:
ENAME      HIREDATE             H          T
SMITH      17-Dec-1980         14          0
ALLEN      20-Feb-1981         13          0
WARD       22-Feb-1981         12          0
JONES      02-Apr-1981         11          0
BLAKE      01-May-1981         10          0
CLARK      09-Jun-1981          9          0
TURNER     08-Sep-1981          8          0
MARTIN     28-Sep-1981          7          0
KING       17-Nov-1981          6          0
JAMES      03-Dec-1981          5          0
FORD       03-Dec-1981          5          0
MILLER     23-Jan-1982          3          0
SCOTT      19-Apr-1987          2          0
ADAMS      23-May-1987          1          0
where the h column is the number of people hired since the hiredat in the output, and the t column is the number of people hired on or after run time, which will, of course, be 0.
You assemble the dynamic SQL statement using || operators to connect strings.  As you pointed out, as string like
TO_DATE ('09/24/2013', 'MM/DD/YYYY')
woule work very nicely, but we're dealing with a DATE, not a string.  We could use TO_CHAR to create a string like that from the given DATE, but there's a much better way.  Pass the cutoff_date in to the dynamic SQL statement as a DATE, using a buind varible, like this:
CREATE OR REPLACE FUNCTION  hired_since
(   table_name   IN  VARCHAR2
,   cutoff_date  IN  DATE
RETURN NUMBER
IS
    return_val  NUMBER;
    sql_txt VARCHAR2 (1000);
BEGIN
    sql_txt := 'SELECT  COUNT (*)'
            || ' FROM ' || table_name
            || ' WHERE  hiredate >= :1';
    dbms_output.put_line (sql_txt || ' = sql_txt in hired_since'); -- For debugging only
    EXECUTE IMMEDIATE sql_txt
    INTO              return_val
    USING             cutoff_date;
    RETURN  return_val;
END  hired_since;
SHOW ERRORS