Alternate to ORDER BY subquery - mysql

Question

From the database at http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_orderby2, for example (Click "Run SQL"), I want to list the customer who has the largest CustomerID that is greater than 80 first among a list of all customers from USA. So I use
SELECT * FROM Customers
WHERE Country = 'USA'
ORDER BY CustomerID = (SELECT MAX(CustomerID) FROM Customers
WHERE CustomerID > 80 AND Country = 'USA') DESC, PostalCode;
but this is not the real query I'm using. If the SELECT... FROM... WHERE... portion of the query is more complex, what is a more elegant query?
The actual query I am trying to modify is
SELECT post.postid, post.visible, post.userid, post.parentid, post.vote_count
FROM " . TABLE_PREFIX . "post AS post
WHERE post.threadid = $threadid
AND post.visible IN (1" . (!empty($deljoin) ? ", 2" : "") .
($show['approvepost'] ? ", 0" : "") . ")
ORDER BY post.postid = {$threadinfo['firstpostid']} DESC, post.vote_count > 5 DESC,
post.dateline $postorder
where the post.vote_count > 5 DESC portion I am trying to replace with only the largest post.vote_count that is larger than 5. So I use:
SELECT post.postid, post.visible, post.userid, post.parentid, post.vote_count
FROM " . TABLE_PREFIX . "post AS post
WHERE post.threadid = $threadid
AND post.visible IN (1" . (!empty($deljoin) ? ", 2" : "") .
($show['approvepost'] ? ", 0" : "") . ")
ORDER BY post.postid = {$threadinfo['firstpostid']} DESC, post.vote_count = (
SELECT MAX(post.vote_count)
FROM " . TABLE_PREFIX . "post AS post
WHERE post.threadid = $threadid
AND post.visible IN (1" . (!empty($deljoin) ? ", 2" : "") .
($show['approvepost'] ? ", 0" : "") . ")
AND post.vote_count > 5
)
DESC, post.dateline $postorder
and all is good. But you can imagine a more complex query, perhaps with INNER JOIN, whose SELECT... FROM... WHERE... etc. must all be duplicated in the subquery.
So my question is, I suspect, can you order query results so the first item (within those results) has the maximum of a field, and the remainder ordered otherwise, without essentially rewriting the entire query in a subquery?

Answer 1

MySQL does not support CTE's, which would have been the perfect solution to simplify your query. They can be emulated with a view though :
CREATE VIEW c AS (SELECT Customer.* FROM Customer WHERE Country = "USA");
SELECT c.* FROM c ORDER BY CustomerID = (SELECT MAX(CustomerID) FROM c) DESC;
DROP VIEW c;
In your case, this would give :
CREATE VIEW p AS (
SELECT post.postid, post.visible, post.userid, post.parentid, post.vote_count
FROM " . TABLE_PREFIX . "post AS post
WHERE post.threadid = $threadid
AND post.visible IN (1" . (!empty($deljoin) ? ", 2" : "") .
($show['approvepost'] ? ", 0" : "") . ")
);
SELECT p.* FROM p
ORDER BY p.postid = {$threadinfo['firstpostid']} DESC, p.vote_count = (
SELECT MAX(p.vote_count)
FROM p
WHERE p.vote_count > 5
)
DESC, post.dateline $postorder;
DROP VIEW p;

Answer 2

This query will list data in descending order of CustomerID
SELECT * FROM Customers
WHERE Country = 'USA'
ORDER BY CustomerID DESC, PostalCode;