hi, i am tryin to update 6 specific records out of 400 odd. Problem is my statement is updating all 400 records.

UPDATE AM_X_422_2
SET
security_level =
(
SELECT
MAX(security_level)
FROM
(
SELECT
code_name,
LENGTH(code_name),
security_level,
mission_date
FROM
AM_X_422_2
ORDER BY
mission_date desc
)
WHERE
rownum < 11
)
WHERE
LENGTH(code_name) > 7
;


I want to update the security level to the highest security level for missions which are within the 10 most recent missions and where length of the first word of the mission code_name exceeds 7 characters.