我该如何进一步优化这个查询?
SELECT * FROM
(SELECT `item`.itemID, COUNT(`votes`.itemID) AS `votes`,
`item`.title, `item`.itemTypeID, `item`.
submitDate, `item`.deleted, `item`.ItemCat,
`item`.counter, `item`.userID, `users`.name,
TIMESTAMPDIFF(minute,`submitDate`,NOW()) AS 'timeMin' ,
`myItems`.userID as userIDFav, `myItems`.deleted as myDeleted
FROM (votes `votes` RIGHT OUTER JOIN item `item`
ON (`votes`.itemID = `item`.itemID))
INNER JOIN
users `users`
ON (`users`.userID = `item`.userID)
LEFT OUTER JOIN
myItems `myItems`
ON (`myItems`.itemID = `item`.itemID)
WHERE (`item`.deleted = 0)
GROUP BY `item`.itemID,
`votes`.itemID,
`item`.title,
`item`.itemTypeID,
`item`.submitDate,
`item`.deleted,
`item`.ItemCat,
`item`.counter,
`item`.userID,
`users`.name,
`myItems`.deleted,
`myItems`.userID
ORDER BY `item`.itemID DESC) as myTable
where myTable.userIDFav = 3 or myTable.userIDFav is null
limit 0, 20
我正在使用MySQL。
谢谢。