Creating function in oracle - database

Question

I am trying to create a function that change the day of a football league; if the match is fixed on saturday then the function update the match day to be the previuos friday, and if the match is fixed on sunday the function update the match date to be on monday. Also the function will show how many rows have been update.
The table I use is as follow:
CREATE TABLE "183400_Matches_Details" (
"183400_Stadiums_id" INTEGER NOT NULL,
"183400_Teams_id" INTEGER NOT NULL,
"183400_Teams_id1" INTEGER NOT NULL,
"183400:Referees_id" INTEGER NOT NULL,
"183400_Matches_number" INTEGER NOT NULL,
"date" DATE NOT NULL,
result VARCHAR2(5) NOT NULL
);
I tried the following statements to build the function, but it always gives me an error:
create or replace function updateDay (
v_number "183400_Matches_Details"."183400_Matches_number"%type)
return date
as
v_fecha "183400_Matches_Details"."date"%type;
begin
SELECT TO_CHAR("date", 'DAY', 'NLS_DATE_LANGUAGE=ENGLISH') as day1 into v_fecha FROM
"183400_Matches_Details"
where "183400_Matches_number" = v_number;
if day1 = 'SATURDAY' then
update "183400_Matches_Details"
set "date" = "date"-1
where "183400_Matches_number" = v_number;
elsif day1 = 'SUNDAY' then
update "183400_Matches_Details"
set "date" = "date"+1
where "183400_Matches_number" = v_number;
end if;
return SQL%ROWCOUNT;
end;
/
select * from "183400_Matches_Details"
DECLARE
v_number "183400_Matches_Details"."183400_Matches_number"%type := &number;
v_total_filas number(8);
BEGIN
v_total_filas := actualizaPrecioCoche(v_number);
DBMS_OUTPUT.put_line('There are ' || v_total_filas || ' updated rows');
END;
/
Any ideas to make it run correctly?=)

Answer 1

I changed your function as it should be. Try below.
CREATE TABLE "183400_Matches_Details"
(
"183400_Stadiums_id" INTEGER NOT NULL,
"183400_Teams_id" INTEGER NOT NULL,
"183400_Teams_id1" INTEGER NOT NULL,
"183400:Referees_id" INTEGER NOT NULL,
"183400_Matches_number" INTEGER NOT NULL,
"datee" DATE NOT NULL,
RESULT VARCHAR2 (5) NOT NULL
);
CREATE OR REPLACE FUNCTION updateDay (
v_number "183400_Matches_Details"."183400_Matches_number"%TYPE)
RETURN DATE
AS
v_fecha "183400_Matches_Details"."datee"%TYPE;
sql_qry VARCHAR2 (400 CHAR);
BEGIN
sql_qry :=
'SELECT TO_CHAR(datee, ''DAY'', ''NLS_DATE_LANGUAGE=ENGLISH'') where "183400_Matches_number"='
|| v_number;
EXECUTE IMMEDIATE sql_qry INTO v_fecha;
IF v_fecha = 'SATURDAY'
THEN
UPDATE "183400_Matches_Details"
SET "datee" = "datee" - 1
WHERE "183400_Matches_number" = v_number;
ELSIF v_fecha = 'SUNDAY'
THEN
UPDATE "183400_Matches_Details"
SET "datee" = "datee" + 1
WHERE "183400_Matches_number" = v_number;
END IF;
RETURN to_date('19000101','yyyymmdd') ;
END;
/

Answer 2

After a second look I realized what your asking is actually quite simple: Given a date that is Sat update it to Fri, and that is Sun update to Mon. This can actually be done in a single SQL statement.
I changed it from a function to a procedure as the purpose is to Update the database, and return the number of rows processed. But as a function it makes the purpose to get the row count and updating the database as a side effect. Names and types (IMHO) should always reflect the purpose of the routine. I did 'return' the row count as an OUT parameter - it being an informational side effect. See fiddle for full example.
create or replace
procedure reschedule_sat_sun_match_details(
p_match_number in "183400_Matches_Details"."183400_Matches_number"%type
, p_rows_updated out number)
as
begin
update "183400_Matches_Details"
set "date" = case to_char("date", 'dy')
when 'sat' then "date"-1 -- Sat update to Fri
when 'sun' then "date"+1 -- Sun update to Mon
end
where to_char("date", 'dy') in ('sat','sun')
and "183400_Matches_number" = p_match_number;
p_rows_updated := sql%rowcount;
end reschedule_sat_sun_match_details;
For day of week values I used the format 'dy' rather than 'day'. The difference being 'dy' returns day name abbreviations with a constant length without padding, while 'day' pads the returned values to the length of the longest day name (to get constant length) thus "sunday" is returned as "sunday " to match the length of "wednesday".
A couple other suggestions. Avoid Mixed Case name and names beginning with numbers. These require double quoting (") on every reference. This becomes a pain to just write and your queries much harder to read and understand. a table name Matches_Details_183400 the exact same information without requiring the quotes. (Yes Oracle will make it upper case in messages it it issues but you can still write it in mixed case if you wish - it will still be the same name.) It gives you no benefit but a lot of pain.
As #hotfix mentioned do not use reserved or keywords as object names. Oracle has documented such words and reserves the right to enforce a specific meaning whenever they choose. If/When they do makes an almost untraceable bug to find.