function does not exist error in PostgreSQL - postgresql

Question

I'm writing procedure in PostgreSQL While writing am getting error for FN_GETCD like
function fn_getcd(integer) does not exist IS THE NEW VALUE
but i have written function for fn_getcd like this
CREATE OR REPLACE FUNCTION public.fn_getcd(
v_entity_num text)
RETURNS timestamp without time zone
LANGUAGE 'plpgsql'
COST 100
STABLE SECURITY DEFINER PARALLEL UNSAFE
AS $BODY$
DECLARE
O_CBD timestamp;
BEGIN
SELECT
TO_DATE(TO_CHAR(clock_timestamp(),'DD-MON-YYYY'),'DD-MON-YYYY')
INTO STRICT
O_CBD
;
RETURN O_CBD;
EXCEPTION
WHEN OTHERS THEN
RETURN O_CBD;
END;
$BODY$;
please help me to solve this error
tocheck :=cast(P_ENTITY_CODE as TEXT);
RAISE NOTICE 'GOT HERE tocheck :% IS THE NEW VALUE',tocheck;
EXECUTE 'INSERT INTO BENMASTHIST SELECT BENMAST_ENTITY_CODE, BENMAST_CUSTOMER_CODE, BENMAST_BEN_CODE,
FN_GETCD(' ||
tocheck || '),' || W_BEN_HIST_SL ||
', BENMAST_NAME, BENMAST_MOBILE_NO,
BENMAST_EMAIL_ID, BENMAST_PHOTO, BENMAST_SOURCE, BENMAST_CR_BY, BENMAST_CR_ON,
BENMAST_MO_BY, BENMAST_MO_ON, BENMAST_AU_BY, BENMAST_AU_ON, TBA_KEY,BENMAST_FROM
FROM BENMAST WHERE BENMAST_ENTITY_CODE =$1 AND BENMAST_CUSTOMER_CODE =$2 AND BENMAST_BEN_CODE =$3'
USING P_ENTITY_CODE, P_CUST_CODE, P_BEN_CODE;
-- RAISE NOTICE 'GOT HERE BENMASTHIST :% IS THE NEW VALUE',BENMASTHIST;
EXCEPTION
WHEN UNIQUE_VIOLATION THEN
P_SUC_FLAG := 'S';
WHEN OTHERS THEN
--- DBMS_OUTPUT.put_line(SQLERRM);
P_SUC_FLAG := 'F';
P_ERROR := SQLERRM;
RAISE NOTICE 'SQLERRM :% IS THE NEW VALUE',SQLERRM;
P_ERROR := 'BENREG013'; --'Error While Inserting Into Benmast';
-- ROLLBACK;
END;

Answer 1

reference: dollar quote: https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-DOLLAR-QUOTING
Sometimes you don't know how much quote you need.You can first compose the string then do the execute command.
a horse already said that you function can be as simple as return current_date::timestamp;
If you add more quote then you function will work.
DO $$
DECLARE
_vstr text := 'test';
_vtime timestamp;
_sql text;
_sql1 text;
_sql0 text;
BEGIN
_sql := ' select fn_getcd( ' || '''' || _vstr || '''' || ' )';
_sql1 := ' select fn_getcd( ' || $a$ '$a$ || _vstr || $b$' $b$ || ' )';
_sql0 := ' select fn_getcd( ' || _vstr || ' )';
RAISE NOTICE '_sql is %', _sql;
RAISE NOTICE '_sql1 is %', _sql1;
RAISE NOTICE '_sql1 is %', _sql0;
EXECUTE _sql INTO _vtime;
RAISE NOTICE 'v_time is % ', _vtime;
END
$$
LANGUAGE plpgsql;
You string is like _sql0 format. You need use dollar quote or simple put more single quote in it. (_sql or _sql1).