Having problem in comparing dates

Question

This is the select statement I run in toad
SELECT CASE WHEN l1 = l2 THEN 'same date' ELSE ' diff date' END AS mydatediff
FROM (SELECT TO_DATE ('2010/03', 'RRRR/MM') l1,
TO_DATE ('201003', 'RRRRMM') l2
FROM DUAL);
Works fine and get results as expected.
For this I have created a function
CREATE OR REPLACE FUNCTION get_same_diff_dat_fun (p_date1 in Varchar2
,p_Date2 in Varchar2)RETURN VARCHAR IS
tmpVar VARCHAR2(25);
Cursor C1 is SELECT CASE WHEN p_date1 = p_date2 THEN 'same date' ELSE ' diff date' END as tmpVar
FROM (SELECT TO_DATE (p_date1, 'RRRR/MM') ,
TO_DATE (p_Date2, 'RRRRMM')
FROM DUAL);
Begin
tmpVar := null;
Open C1;
Fetch C1 into tmpVar;
Close C1;
RETURN tmpVar;
EXCEPTION
WHEN NO_DATA_FOUND THEN
NULL;
WHEN OTHERS THEN
-- Consider logging the error and then re-raise
RAISE;
END get_same_diff_dat_fun;
Function works fine when I run in toad
select get_same_diff_dat_fun(to_date('2010/03','RRRR/MM'),to_date('201003','RRRRMM')) from dual
In the form I need to use this to compare the fields
Form filed is exp_date with date datatype
I have exp_date in the table called supplies_receiving. In the database it is defined as date.
In the form I have the field as date in format RRRRMM
I and not getting results. I have error message and its not even going to the error. When I type in date as 201003
the cursor comes back to the filed and stops. What is th reason. I need to solve this. Any help is appreciated.

Answer 1

First of all, you are doing a TO_DATE() on a date passed in. You should ONLY use TO_DATE on a text field, never on a date.
Second, why are you using a Select from Dual? You can simply do a PL/SQL date comparison, without the overhead of asking the Oracle database to do it.
And what is the RETURN VARCHAR?   Change it to RETURN VARCHAR2
And this is all you need. Note the Trunc(...'MM') functions. It removes any time element and day-of-month element from the input date parameters, so you effectively are only comparing month and year in the two dates. I am assuming that is what you want to do, since you are using the YYYYMM format everywhere.
<pre><font face = "Lucida Console, Courier New, Courier, Fixed" size = "1" color = "navy">CREATE OR REPLACE FUNCTION get_same_diff_dat_fun
(p_date1 in Varchar2,
p_Date2 in Varchar2)
RETURN VARCHAR2 is
Begin
If trunc(p_date1,'MM')
= trunc(p_date2,'MM') then
Return 'same date';
Else
Return 'diff date';
End if;
End;</font></pre>
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