Temporary Table and Set Variables mysql --- UPDATES - mysql

Question

I want to both create a temporary table and utilize a variable. I have consulted the documentation and I believe the syntax is correct but putting them together is giving me an error.
My goal is to create a date variable that is always 1 year before now() and will populate my temporary table with one month increment rows until the present moment. Any help would be greatly appreciated.
Error:
"Error: 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 'SET #start_date = DATEADD(year, -1 ,GETDATE())\n\n WHILE #start_date < GETD' at line 4"
Here is my SQL statement.
CREATE TEMPORARY TABLE helper(
date datetime not null
);
SET #start_date = DATEADD(year, -1 ,GETDATE())
WHILE #start_date < GETDATE()
BEGIN
INSERT INTO helper VALUES (#start_date)
SELECT #start_date = DATEADD(MONTH, 1, #start_date)
END
update 1
with this code I am still receiving a syntax error
CREATE TEMPORARY TABLE helper(
date datetime not null
);
insert into helper (date)
with recursive cte as (
select curdate() - interval 12 month as date
union all
select date + interval 1 month
from cte
where date < curdate()
)
select date from cte;
select * from helper;
error
"Error: 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 'insert into helper (date)\n with recursive cte as (\n select c' at line 4",
UPDATE 2
I have changed the syntax to this. I am still getting errors but it seems to be closer to mySql 5.7
`
CREATE TEMPORARY TABLE helper(
date datetime not null
);
CREATE PROCEDURE dowhile()
BEGIN
DECLARE date datetime DEFAULT SUBDATE(curdate(), interval 12 month);
WHILE date < curDate() DO
INSERT INTO helper VALUES(date);
SET date = date + interval 1 month;
END WHILE;
END;
DELIMITER;
CALL dowhile()
SELECT date_format(log.entry_stamp, '%Y-%M') AS 'date', COUNT(log.element_id) as count FROM dm_log log
INNER JOIN dm_element el
ON el.element_id = log.element_id
WHERE ? = el.dm_id
LEFT OUTER JOIN helper h
ON h.date = log.date
GROUP BY date
ORDER BY date;
DROP TEMPORARY TABLE helper;
`
Error
"Error: 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 'CREATE PROCEDURE dowhile()\n BEGIN\n DECLARE date datetime DEFAU' at line 4",

Answer 1

You can use a recursive CTE instead of a WHILE loop:
insert into helper (date)
with recursive cte as (
select curdate() - interval 12 month as date
union all
select date + interval 1 month
from cte
where date < curdate()
)
select date from cte;
Here is a db<>fiddle.
Note that MySQL does not use getdate(). And doesn't support while loops outside of programming blocks. And doesn't have a three-argument form of dateadd(). It looks like you are confusing MySQL with SQL Server.
In earlier versions, you'll probably need to list the values explictly:
insert into helper (date)
select curdate() union all
select curdate() - interval 1 month union all
. . .;