Dynamic Query for 'Select IN' -- URGENT!!!

Question

I've got the following Select statement -
SELECT Employee_Name, SSN FROM Company
WHERE EMPLOYEE_NAME IN (c_Employee_Name) ;
Here c_Employee_Name is a Returned RefCursor from another function. It gives error as Type mismatch.
Is there anyway I can run one SELECT statement for all the Employee_Name returned by the function?
Any sample code will be great.
Thanks a lot,
Suman

Answer 1

If you have a packaged function that returns a ref cursor,
something like this:
CREATE OR REPLACE PACKAGE package_name
AS
  TYPE c_employee_name IS  REF cursor;
  FUNCTION function_name
    (p_tables      IN  VARCHAR2,
     p_columns     IN  VARCHAR2 DEFAULT '*',
     p_where       IN  VARCHAR2 DEFAULT ' 1 = 1 ',
     p_others      IN  VARCHAR2 DEFAULT NULL)
    RETURN package_name.c_employee_name;
END package_name;
CREATE OR REPLACE PACKAGE BODY package_name
AS
  FUNCTION function_name
    (p_tables      IN  VARCHAR2,
     p_columns     IN  VARCHAR2 DEFAULT '*',
     p_where       IN  VARCHAR2 DEFAULT ' 1 = 1 ',
     p_others      IN  VARCHAR2 DEFAULT NULL)
    RETURN package_name.c_employee_name
  IS
    v_sql              VARCHAR2 (4000) := NULL;
    v_results          package_name.c_employee_name;
  BEGIN
    v_sql :=
       ' SELECT ' || p_columns
    || ' FROM '   || p_tables
    || ' WHERE '  || p_where || ' '
    || p_others;
    OPEN v_results FOR v_sql;   
    RETURN v_results;
  END function_name;
END package_name;
Then, you can use a procedure, something like the
one below, to call the function and loop through
the ref cursor to concatenate a string of employee
names to be used in the select statement.  You can
then open another ref cursor for that select statment
and process the results however you like.  I used
dbms_output in the following example:
CREATE OR REPLACE PROCEDURE procedure_name
AS
  c_employee_names  package_name.c_employee_name;
  v_employee_name   company.employee_name%TYPE;
  v_employee_names  VARCHAR2 (4000) := NULL;
  v_delimiter       VARCHAR2 (1) := NULL;
  v_sql             VARCHAR2 (4000) := NULL;
  TYPE cursor_type IS REF CURSOR;
  cursor_name cursor_type;
  v_ssn             company.ssn%TYPE;
BEGIN
  c_employee_names := package_name.function_name
                        ('company', 'employee_name');
  LOOP
    EXIT WHEN c_employee_names%NOTFOUND;
    FETCH c_employee_names INTO v_employee_name;
    v_employee_names := v_employee_names
    || v_delimiter
    || v_employee_name;
    v_delimiter := ',';
  END LOOP;
  v_employee_names := REPLACE (v_employee_names, ',', ''',''');
  v_sql := ' SELECT employee_name, ssn'
        || ' FROM   company'
        || ' WHERE  employee_name IN ('''
        || v_employee_names
        || ''')';
  OPEN cursor_name FOR v_sql;
  LOOP
    EXIT WHEN cursor_name%NOTFOUND;
    FETCH cursor_name INTO v_employee_name, v_ssn;
    DBMS_OUTPUT.PUT_LINE (v_employee_name || ' ' || v_ssn);
  END LOOP;
  CLOSE cursor_name;
END procedure_name;
To execute the procedure that calls the function:
SET SERVEROUTPUT ON
EXEC procedure_name