Benjamin, Benjamin Pflugmann wrote:
> Hi. > > I guess your "problem" comes from the fact that SQL has no concept of > internal order. If you do not specify an ORDER BY clause, the order or > records returned is undefined, i.e. random. That's what I was figuring. I asked because I wanted it confirmed. Thank you. > > > Of course, MySQL has some kind of internal order depending on many > factors, but you may not rely on it. And neither you may rely on the > fact that a PRIMARY KEY influences the internal order. You have to use > an ORDER BY clause if you want to get a sorted result (of course, you > want a key to speed up the ORDER BY clause). Hmmm. Perhaps I'm misled by the default behaviour of other database engines, but I was taught that the primary key was stored in the database to optimize search/insert/delete - which meant *sorted*. That is why you don't want a large (complex) primary key on tables that must run "fast" - the overhead of sorting each insert/delete negatively affects performance. Or so I was taught, anyway (back in the dark ages - primative data structures and all that <G>). Cheers, -Richard > > > As said, the (sorting) behaviour without ORDER BY is undefined > according to the specification and may change without notice. > > Bye, > > Benjamin. > > On Mon, Mar 04, 2002 at 09:56:53PM -0700, [EMAIL PROTECTED] wrote: > > Greetings! > > > > If you do not have an index on any column in a table, how does mysql > > handle repeated queries (i.e. SELECT * FROM report;) > > > > I am noticing that if I run the following three queries, I get different > > results for the third query: > > > > SELECT * FROM report; > > SELECT * FROM report ORDER BY lastname; > > SELECT * FROM report; > > > [...] > > p.s. This is for my understanding. I solved my actual problem by simply > > placing a primary key on the appropriate columns - as I should have from > > the beginning! <G>). > [...] > > -- > [EMAIL PROTECTED] --------------------------------------------------------------------- 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
