Question

okay, my problem is a little bit more difficult than the title would tell…

i have a table with messages, i load all these messages in php using a while loop.

my sql query looks like this at the moment:

"SELECT * 
 FROM messages 
 WHERE thread_id = '" . $thread_id . "'
 ORDER BY date_sent"

works fine and returns all the messages after one another, so that i have the latest message at the bottom (which is important, since my messaging module works like facebook, with a small reply field at the bottom, to let the users chat directly)

now, what i’d like to have is a query that would give me only the latest 10 results in a single query.

i already have the number of wanted results ($number_of_results = 10;)

it’d be really cool, if i didn’t have to count the rows of the result first, but rather would request the result in a single query.

something like:

"SELECT * 
 FROM messages 
 WHERE thread_id = '" . $thread_id . "'
 ORDER BY date_sent 
 LIMIT TOTAL_NUMBER_OF_ROWS_WHERE_THREAD_ID_IS_MY_THREAD_ID-$number_of_results, $number_of_results"

is there a way to do something like this…?

Answer 1

"SELECT * 
 FROM messages 
 WHERE thread_id = '" . $thread_id . "' 
 ORDER BY date_sent DESC 
 LIMIT 10";

Make sure you have this index

ALTER TABLE messages 
ADD INDEX threadid_datesent_ndx( thread_id, date_sent );

If you want the 10 reversed again, then do this:

"SELECT * 
 FROM
 (
     SELECT * 
     FROM messages 
     WHERE thread_id = '" . $thread_id . "' 
     ORDER BY date_sent DESC LIMIT 10
 ) A
 ORDER BY date_sent";