MySQL Error 1064 when create function - mysql

Question

When I am trying to create a function in mysql 5.7.20, I met error 1064:
delimiter //
create function add_favorstocks (
uid_int INT,
stockid_char CHAR(20),
added_date CHAR(20)
)
returns INT
begin
declare ret INT;
case
when exists (select 1 from user_favorstocks where uid=uid_int and stockid = stockid_char)
then begin
insert into user_favorstocks (uid, stockid, added_date) values (uid_int, stockid_char, added_date);
set ret=1;
end
else
begin
case (select is_deleted from user_favorstocks where uid=uid_int and stockid = stockid_char)
when 0 then set ret=0;
else begin
update user_favorstocks set is_deleted=0, db_update_time=now() where uid=uid_int and stockid=stockid_char;
set ret=3;
end;
end
end
end
return ret
end//
delimiter ;
The error message is
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'else
begin
case (select is_deleted from user_favorstocks whe' at line 15
Does this because that I am using begin...end in an else clause?
I found the example in MySQL's documentation:
DELIMITER |
CREATE PROCEDURE p()
BEGIN
DECLARE v INT DEFAULT 1;
CASE v
WHEN 2 THEN SELECT v;
WHEN 3 THEN SELECT 0;
ELSE
BEGIN
END;
END CASE;
END;
|
It seems valid to use a begin...end statement in an else clause.

Answer 1

Try:
DROP FUNCTION IF EXISTS `add_favorstocks`;
delimiter //
create function add_favorstocks (
uid_int INT,
stockid_char CHAR(20),
added_date CHAR(20)
)
returns INT
begin
declare ret INT;
case when exists (select 1
from user_favorstocks
where uid=uid_int and
stockid = stockid_char)
then begin
insert into user_favorstocks
(uid, stockid, added_date)
values
(uid_int, stockid_char, added_date);
set ret=1;
-- end <-- missing a semicolon
end;
else
begin
case (select is_deleted
from user_favorstocks
where uid=uid_int and
stockid = stockid_char)
when 0 then set ret=0;
else begin
update user_favorstocks
set is_deleted=0,
db_update_time=now()
where uid=uid_int and
stockid=stockid_char;
set ret=3;
end;
-- end <-- missing CASE and a semicolon
end case;
-- end <-- missing a semicolon
end;
-- end <-- missing CASE and a semicolon
end case;
-- return ret <-- missing a semicolon
return ret;
end//
delimiter ;