MYSQL select last 3 rows, order by ASC

问题

I just want to select the newest 3 comments on a post, and have them ordered in ASC order.

This selects the last 3 rows, however I need them in the reverse order:

mysql_query("
SELECT * FROM comments WHERE postID='$id' AND state='0' ORDER BY id DESC LIMIT 3")

回答1:

You can reverse sort it later.

SELECT * 
FROM (SELECT * FROM comments
      WHERE postID='$id' 
        AND state='0' 
      ORDER BY id DESC 
      LIMIT 3) t
ORDER BY id ASC;

回答2:

This can also be done just in PHP, without modifying the SQL query, by simply iterating backwards through the result set:

$res = mysql_query(...);
for($i=mysql_num_rows($res)-1; $i>=0; $i--) {
    //do whatever
}

I confess I don't know what the performance difference is (if any), but it's just another option that might suite you.

回答3:

$result = mysqli_query($con,"SELECT * FROM (SELECT * FROM messeges WHERE username='{$_SESSION['username']}' ORDER BY id DESC LIMIT 3) t ORDER BY id ASC");

来源：https://stackoverflow.com/questions/8891060/mysql-select-last-3-rows-order-by-asc