Order by DESC reverse result

Question

I'm retrieving some data in SQL, order by DESC. I then want to reverse the result. I was doing this by pushing the data into an array and then using array_reverse , but I am finding it's quite taxing on CPU time and would like to simply use the correct SQL query.

I've looked at this thread SQL Server reverse order after using desc , but I cannot seem to make it work with my query.

SELECT live.message,
       live.sender,
       live.sdate,
       users.online
FROM live, users
WHERE users.username = live.sender
ORDER BY live.id DESC
LIMIT 15

Answer 1

You can place your query into a subquery and then reverse the order:

SELECT t.message,
       t.sender,
       t.sdate,
       t.online
FROM
(
    SELECT live.id,
           live.message,
           live.sender,
           live.sdate,
           users.online
    FROM live
    INNER JOIN users
        ON users.username = live.sender
    ORDER BY live.id DESC
    LIMIT 15
) t
ORDER BY t.id ASC

You'll notice that I replaced your implicit JOIN with an explicit INNER JOIN . It is generally considered undesirable to use commas in the FROM clause (qv the ANSI-92 standard) because it makes the query harder to read.

Answer 2

You could wrap your query with another query and order by with asc . Since you want to order by live.id , you must include it in the inner query so the outer one can sort by it:

SELECT   message, sender, sdate, online 
FROM     (SELECT   live.message, live.sender, live.sdate, users.online, live.id 
          FROM     live, users
          WHERE    users.username = live.sender 
          ORDER BY live.id DESC 
          LIMIT    15) t
ORDER BY id ASC