At 10:12 -0700 9/23/02, neal wrote: >I just presume that this will add alot of overhead to the query. The reason >I wanted to be able to do something like a union rather than seperate >queries is because of overhead. I dunno ... am I wrong? Is it not that >bad?
The way to find out is to try it. Queries that generate large result sets are likely to write to disk anyway, even without an explicitly created table. > >Also, I tried the query you suggested ... can you really do this(?): >"insert into tmp select userId from iteneraries" > >I was getting an error 'near insert into'. It seems you're trying to >execute a subquery within a query ... can MySQL do this? It's not a subquery. The example I showed below consists of three separate queries. Make sure to terminate each with a semicolon. From the error message you describe, it sounds as though you may have issued them all as a single statement. > >Thanks. >Neal > > > >-----Original Message----- >From: Paul DuBois [mailto:[EMAIL PROTECTED]] >Sent: Monday, September 23, 2002 10:09 AM >To: neal; mySQL >Subject: RE: multi-table select (not a join) > > >At 9:55 -0700 9/23/02, neal wrote: >>Thanks for the suggestion but this would actually create a new table, >>correct (the first statement that is)? I just want a resultset with these >>values, without writing to disk. > >Then you must upgrade to 4.x so that you have UNION support. >Either that, or write a client program that issues multiple SELECT >statements and buffers the results in memory. > >What's your objection to creating the new table? Just delete it when >you're done with it. > >> >>On another note, yeah youre right not a different connection object, but I >>presume I would need to run two seperate queries and recieve back two >>seperate resultsets. >> >>Neal >> >> >>-----Original Message----- >>From: Paul DuBois [mailto:[EMAIL PROTECTED]] >>Sent: Monday, September 23, 2002 9:21 AM >>To: neal; mySQL >>Subject: RE: multi-table select (not a join) >> >> >>At 0:23 -0700 9/23/02, neal wrote: >>>Oh man! >>> >>>Yeah, you're right. That's exactly what I want but apparently it wasn't >>>implemented until v4??!?!?! >> >>Right. >> >>> >>>What did people do prior to version 4 when needing to query multiple >>tables? >>>Just endure the overhead of multiple connections to the database? >> >>Not sure why you'd need multiple *connections*. You can use multiple >>*queries*, for example like this: >> >>CREATE TABLE tmp SELECT ... FROM t1 ... >>INSERT INTO tmp SELECT ... FROM t2 ... >>INSERT INTO tmp SELECT ... FROM t3 ... >> >>At the end of this, tmp will be the same as if you'd done UNION. >>More precisely, as if you'd done UNION ALL, because duplicates won't >>be removed. To remove them, use SELECT DISTINCT when retriving from >>tmp. >> >>> >>>Thanks. >> >Neal --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
