Yes, you are correct in assuming that, but ONLY if you use MyISAM tables.
BDB and ISAM tables reuse number, kind of.
Ex:
1
2
3
4
5
If you delete 5, the next record you insert will have an ID of 5. If you
delete 4 instead of 5, the next one inserted will have an ID of 6. So, BDB
and ISAM tables do kind of a MAX(id)+1, whereas MyISAM tables actually keep
track of the last used auto increment number.
Hope that helps!
j----- k-----
On Friday 20 July 2001 17:11, you wrote:
> That I'm trying to do here is get the VALUE of hit_id from the last row of
> hits. It is an auto-increment number, but it is much higher than the count
> of the rows, because people go through and delete their hits from time to
> time. Am I correct in assuming that auto-numbers are never re-used?
>
> Walter
>
> On 7/20/01 7:06 PM, "Joshua J. Kugler" <[EMAIL PROTECTED]> wrote:
> > Read the manual again on last_insert_id(). That function only gives you
> > the unique id of the last insert *for that thread* If you connect, don't
> > do any inserts, and select last_insert_id, there is no guarentee what you
> > will get. If you are trying to find the number of rows, it would be much
> > easier to do this:
> >
> > SELECT COUNT(*) AS pixels FROM hits
> >
> > Try that. From the looks of what you are doing, that will be accurate
> > every time. COUNT(*) knows how many rows there are in a table.
> > last_insert_id() has nothing to do with how many rows are in a table.
> >
> > If you are going to delete old rows one day, then you might want to do
> > this:
> >
> > SELECT MAX(id) as pixels FROM hits
> >
> > Hope that helps.
> >
> > On Friday 20 July 2001 13:31, Walter Lee Davis wrote:
> >> Currently, I have been counting the rows in PHP in order to get the
> >> value of the last hit_id in the database like this:
> >>
> >> $sql4 = "SELECT hits.hit_id from hits";
> >>
> >> $result = mysql_query ($sql4, $connection)
> >> or die("error #" . mysql_errno() . ": " . mysql_error());
> >> $last = mysql_num_rows($result) - 1;
> >> $go = mysql_data_seek($result, $last);
> >> $row = mysql_fetch_object($result);
> >> $pixels = number_format($row->hit_id);
> >>
> >> Which is really expensive on my very tall hits table. I hit upon doing
> >> it in MySQL, which is much, much faster:
> >>
> >> $sql4 = "SELECT hits.hit_id
> >> as pixels
> >> from hits
> >> WHERE hit_id=LAST_INSERT_ID();";
> >>
> >> $result = mysql_query ($sql4, $connection)
> >> or die("error #" . mysql_errno() . ": " . mysql_error());
> >> $row = mysql_fetch_object($result);
> >> $pixels = number_format($row->pixels);
> >>
> >> It's staggering the difference in speed. But if I sit there and hit
> >> refresh on the browser, I get wildly different values for $pixels. It
> >> jumps around the actual number by +-10 or 12. The first method is
> >> precisely the same every time (unless a hit is recorded in the interim).
> >> Am I doing something wrong here? Can I not count on MySQL to know how
> >> many rows it has recorded in a table? Any idea why that select statement
> >> would select a different row each time?
--
Joshua Kugler, Information Services Director
Associated Students of the University of Alaska Fairbanks
[EMAIL PROTECTED], 907-474-7601
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