MyChenQL, part 5

[filburt1]

How can I make this into valid SQL for MySQL (i.e., dump the nested query):
[sql]
SELECT pagetext FROM post WHERE threadid =
(SELECT threadid FROM thread WHERE forumid = 18 ORDER BY dateline DESC LIMIT 1)
ORDER BY dateline ASC LIMIT 1
[/sql]

English: select the pagetext from the first post in the most recent thread in forum 18.

[okrogius]

SELECT post.pagetext, thread.dateline, thread.forumid FROM post, thread WHERE thread.forumid=18 && post.threadid=thread.threadid ORDER BY thread.dateline ASC LIMIT 1;

Try that.

[Chris M]

SELECT post.*, thread.* FROM post LEFT JOIN thread ON post.threadid=thread.threadid WHERE thread.forumid=18 ORDER BY thread.dateline ASC LIMIT 1;



Satan

[filburt1]

Now which one would be the least server-intensive? I vaguely remember Chen saying something about never joining the post and thread tables...

[Herman]

xD you could always use the Union (i just learnt it an hour ago) it joins multiple queries to one and really increases load time...

[Xenon]

@filburt: i'd use Codenames version, i think it's faster here.
Joining is needed for other issues.

[filburt1]

Okay, will try

[okrogius]

Never use SELECT * unless you need it. Of course, there is an exception - if you lack common sense it won't matter .