Oracle - change columns in WHERE clause based on input - oracle

Question

I want use separate columns in WHERE clause based on the INPUT received in the stored procedure.
If TYPE_DEFINITION = 'SUP' then use SUPPLIER column
If TYPE_DEFINITION = 'CAT' then use CATEGORY column
I know I can write two separate SELECT's using a CASE statement, but that will be very dumb and redundant. Any cleaner way of doing it?
CREATE OR REPLACE PROCEDURE SG.STORED_PROCEDURE (
TYPE_DEFINITION IN VARCHAR2,
VALUE IN VARCHAR2,
STORELIST IN VARCHAR2)
AS
BEGIN
SELECT O.ORGNUMBER,
S.SKU,
FROM SKU S JOIN ORG O ON S.ORGID = O.ORGID
WHERE
AND O.ORGNUMBER IN (STORELIST)
AND (CASE TYPE_DEFINITION
WHEN 'SUP' THEN S.SUPPLIER = VALUE
ELSE S.CATEGORY = VALUE
END);
END;
/

Answer 1

Your code is very close. The CASE THEN must return an expression, not a condition. But the CASE can be used as part of a condition, just move the = VALUE
to the outside.
Change this:
AND (CASE TYPE_DEFINITION
WHEN 'SUP' THEN S.SUPPLIER = VALUE
ELSE S.CATEGORY = VALUE
END);
To This:
AND VALUE = (CASE TYPE_DEFINITION
WHEN 'SUP' THEN S.SUPPLIER
ELSE S.CATEGORY
END);
Your code makes sense. This limitation is probably a result of Oracle not fully supporting Booleans.
UPDATE
If you run into performance problems you may want to use dynamic SQL or ensure that the static SQL is correctly using FILTER operations. When Oracle builds an execution plan it is able to use bind variables like constants, and choose a different plan based on the input. As Ben pointed out, these FILTER operations don't always work perfectly, sometimes it may help if you use simplified conditions like this:
(TYPE_DEFINITION = 'SUP' AND S.SUPPLIER = VALUE)
OR
((TYPE_DEFINITION <> 'SUP' OR TYPE_DEFINITION IS NULL) AND S.CATEGORY = VALUE)

Answer 2

You need to use dynamic sql in your procedure.
Something like this:
CREATE OR REPLACE PROCEDURE SG.STORE_PROC (
TYPE_DEFINITION IN VARCHAR2,
VALUE IN VARCHAR2,
STORELIST IN VARCHAR2)
AS
TYPE EmpCurTyp IS REF CURSOR;
v_emp_cursor EmpCurTyp;
v_stmt_str VARCHAR2(200);
v_orgnumber VARCHAR2(200);
v_sku VARCHAR2(200);
BEGIN
v_stmt_str := 'SELECT O.ORGNUMBER, S.SKU,FROM SKU S JOIN ORG O ON S.ORGID = O.ORGID ';
if type_definition = 'SUP' then
v_stmt_str := v_stmt_str || 'WHERE s.supplier = :v';
else
v_stmt_str := v_stmt_str || 'WHERE s.category = :v';
end if;
-- Open cursor & specify bind variable in USING clause:
OPEN v_emp_cursor FOR v_stmt_str USING value;
-- Fetch rows from result set one at a time:
LOOP
FETCH v_emp_cursor INTO v_orgnumber, v_sku;
-- you can do something here with your values
EXIT WHEN v_emp_cursor%NOTFOUND;
END LOOP;
-- Close cursor:
CLOSE v_emp_cursor;
END;
/