PLSQL: using subquery in if-statement error PLS-00405 - sql

Question

I'm getting error pls-00405 when I try to run this code:
BEGIN
IF :P10_KAART_CODE IN (SELECT KAART_CODE FROM CADEAUKAART) THEN
RETURN TRUE;
ELSE
RETURN FALSE;
END IF;
END;
There are some similar questions about this but couldn't find a solution for this simple code. Is there another way of writing this without facing a error?

Answer 1

PL/SQL doesn't support embedded SQL in if statements. So you'll need to rewrite your code like this:
create or replace function validate_kaart_code
(P10_KAART_CODE in CADEAUKAART.KAART_CODE%type)
return boolean
is
rv boolean;
l_code CADEAUKAART.KAART_CODE%type;
BEGIN
begin
SELECT KAART_CODE into l_code
FROM CADEAUKAART
where KAART_CODE =:P10_KAART_CODE
and rownum = 1 -- only necessary if KAART_CODE is not unique
;
rv := TRUE;
exception
when no_data_found then
rv := FALSE;
end;
RETURN rv;
END;
I have attempted to reconstruct your whole functionality from the snippet you posted. If this isn't what you intended and you can't convert it to fit your needs please provide more details.

Answer 2

I'd move the condition to the query itself, and catch a NO_DATA_FOUND exception:
BEGIN
SELECT * FROM CADEAUKAART WHERE kaart_code = :P10_KAART_CODE;
RETURN TRUE;
EXCEPTION WHEN NO_DATA_FOUND THEN
RETURN FALSE;
END;

Answer 3

One more way:
CREATE OR REPLACE FUNCTION IS_KAART_CODE_VALID(pinKAART_CODE IN CADEAUKAART.KAART_CODE%TYPE)
RETURN BOOLEAN
IS
nCount NUMBER;
BEGIN
SELECT COUNT(*)
INTO nCount
FROM CADEAUKAART
WHERE KAART_CODE = pinKAART_CODE ;
RETURN CASE
WHEN nCount > 0 THEN
TRUE
ELSE
FALSE
END;
END IS_KAART_CODE_VALID;

Answer 4

You may try a cursor, alternatively :
DECLARE
v_flag boolean := FALSE;
BEGIN
FOR c IN ( SELECT KAART_CODE FROM CADEAUKAART )
LOOP
IF :P10_KAART_CODE = c.KAART_CODE THEN
v_flag := TRUE;
EXIT;
END IF;
EXIT WHEN NO_DATA_FOUND;
END LOOP;
RETURN v_flag;
END;
By your way using a select statement is not allowed, you might list all the members for the returning values of KAART_CODE such as
IF :P10_KAART_CODE IN ('aAA','BBb','ccC'..) THEN
but which is not preferable and nice to list all matching values .