Hello my friends, I need your important help.

I tried this join query:
Code:
SELECT
	A.password,
        A.email,
	B.email
FROM
	tbl_login A
JOIN tbl_ml B ON A.email = B.email
WHERE
	1
ORDER BY
	ID DESC;
In output I have in the column `password` of the tbl_login some rows with NULL value.

When the field `password` of the tbl_login is NULL value I need update NULL value with alphanumeric string random.

Can you help me?
Thanks in advance