package

CREATE OR REPLACE PACKAGE poly_pkg AS 
 
  FUNCTION describe (p_tbl IN OUT DBMS_TF.TABLE_T )  
           RETURN DBMS_TF.DESCRIBE_T; 
 
END; 

package body

CREATE OR REPLACE PACKAGE BODY poly_pkg AS  
  
  FUNCTION describe (p_tbl IN OUT DBMS_TF.TABLE_T )  
           RETURN DBMS_TF.DESCRIBE_T AS  
  BEGIN  
  
    -- what schema is the table from?  
    DBMS_OUTPUT.PUT_LINE('Table Schema ' ||   
                          p_tbl.schema_name);  
    -- what package is being run?  
    DBMS_OUTPUT.PUT_LINE('Table Package ' ||   
                          p_tbl.package_name);  
    -- What PTF is being run?  
    DBMS_OUTPUT.PUT_LINE('Table PTF ' ||   
                          p_tbl.ptf_name);  
  
    -- the column array in the DBMS_TF_TABLE_T  
    -- structure contains details of each column  
    FOR counter IN 1..p_tbl.column.count LOOP  
  
      DBMS_OUTPUT.PUT_LINE('Column ' || counter);  
      -- output the column name, the length of the  
      -- column name, the maximum value length allowed  
      -- and the data type of the column  
      DBMS_OUTPUT.PUT_LINE('- Name ' ||   
              p_tbl.column(counter).description.name);  
      DBMS_OUTPUT.PUT_LINE('- Name Len ' ||   
              p_tbl.column(counter).description.name_len);  
      DBMS_OUTPUT.PUT_LINE('- Max Len ' ||   
              p_tbl.column(counter).description.max_len);  
      DBMS_OUTPUT.PUT_LINE('- Datatype ' ||   
              p_tbl.column(counter).description.type);  
  
    END LOOP;  
  
    RETURN NULL;  
  END;  
END; 

function

CREATE OR REPLACE FUNCTION poly_func(p_tbl IN TABLE) 
  RETURN TABLE PIPELINED  
  ROW POLYMORPHIC USING poly_pkg; 

demo table

CREATE TABLE table1  
( col1 NUMBER,  
  col2 NUMBER )

demo data

INSERT INTO table1  
VALUES(19,99)

demo query

SELECT *  
  FROM poly_func(table1)