How to Select a Variable As Query Result in Oracle PLSQL - oracle

Question

I've looked high and low but have not been able to figure this out.
I have this function defined in Oracle:
FUNCTION MY_FUNCTION(
INPUTVAR1 IN OUT NUMBER,
INPUTVAR2 VARCHAR2
) RETURN NUMBER;
The person who created this function is basically returning the input parameter if it's not 0. Otherwise if INPUTVAR1 is 0, it will return a new value. I want that new value.
In T-SQL it's so simple it's stupid:
DECLARE #MyVar INT = 0;
SET #MyVar = MY_FUNCTION(#MyVar, NULL);
SELECT #MyVar as Result;
But In Oracle, I cannot figure out how to return the return value as a result. This is what I have so far:
DECLARE MyVar NUMBER := 0;
BEGIN
MyVar := MY_FUNCTION(INPUTVAR1 => MyVar, INPUTVAR2 => NULL)
END;
But I can't figure out how to use MyVar in the result. I definitely cannot select it. I tried DBMS_OUTPUT.PUT_LINE(MyVar); but no luck.
Anyone know how I can return the value of MyVar?

Answer 1

So I was able to find this solution which works only if you have 12c or above JDBC drivers:
DECLARE MyVar NUMBER := 0;
rc sys_refcursor;
BEGIN
MyVar := MY_FUNCTION(INPUTVAR1 => MyVar, INPUTVAR2 => NULL)
open rc for SELECT MyVar FROM dual;
dbms_sql.return_result(rc);
END;
I'd like to meet the person who thought it was a good idea to have a FUNCTION with both IN/OUT parameters and a return value.

Answer 2

Redefine the function to not having an OUT parameter:
CREATE FUNCTION MY_FUNCTION(
INPUTVAR1 IN NUMBER,
INPUTVAR2 IN VARCHAR2
) RETURN NUMBER
IS
BEGIN
RETURN INPUTVAR1;
END;
/
Then you can use it in an SQL query:
SELECT MY_FUNCTION( INPUTVAR1 => 0, INPUTVAR2 => NULL ) AS value
FROM DUAL
Output:
| VALUE |
| ----: |
| 0 |
db<>fiddle here
Update
If you cannot redefine the function to remove the OUT parameter then write a wrapper around it:
CREATE FUNCTION MY_FUNCTION_WRAPPER(
INPUTVAR1 IN NUMBER,
INPUTVAR2 IN VARCHAR2
) RETURN NUMBER
IS
var1 NUMBER := INPUTVAR1;
BEGIN
RETURN MY_FUNCTION( INPUTVAR1 => var1, INPUTVAR2 => INPUTVAR2 );
END;
/
Then you can call it from an SQL statement:
SELECT MY_FUNCTION_WRAPPER( INPUTVAR1 => 0, INPUTVAR2 => NULL ) AS value
FROM DUAL;
Output:
| VALUE |
| ----: |
| 0 |
db<>fiddle here

Answer 3

dbms_output works fine for me:
create or replace FUNCTION MY_FUNCTION(
INPUTVAR1 IN OUT NUMBER,
INPUTVAR2 VARCHAR2
) RETURN NUMBER is
begin
if inputvar1 = 0 then
return -1;
else
return inputvar1;
end if;
end;
/
declare
my_var number := 0;
my_var2 number := 0;
begin
my_var2 := my_function(my_var, 'A');
dbms_output.put_line('my_var:' || my_var);
dbms_output.put_line('my_var2:' || my_var2);
end;
/
my_var:0
my_var2:-1
Edit: I am a little concerned about having an OUT variable in a function. That's usually a sign of poor coding, which is why I used 2 variables above, so you could see whether the function was "returning" the new value by modifying INPUTVAR1, or by using the return value. Or both.

Answer 4

Your original Oracle code, with dbms_output, is correct. Basically, after calling a function you use the assigned variable exactly as if you had assigned it a value (same as SQL Server).
So a function call "x := some_function(y)" that returns a value (lets say 9), is after the call exactly the same as if you had written "x := 9". So again your function was correct.
However, you indicated you use SQL Developer. My guess is you didn't have dbms_output turned on. To do that on SQL Developer menu bar select View then click Dbms output. This will open a dbms_output window. But your not quite done. It the Dbms output window click the large green +, select the appropriate schema (if needed) and click ok. Dbms_output will now be shown in that window.

Answer 5

try this
DECLARE MyVar NUMBER := 0;
varout VARCHAR2();
BEGIN
--MyVar := MY_FUNCTION(INPUTVAR1 => MyVar, INPUTVAR2 => NULL)
select MY_FUNCTION(INPUTVAR1 => MyVar, INPUTVAR2 => NULL) INTO varout from dual;
dbms_output.put_line(MyVar);
END;