> -----Original Message-----
> From: Peter Brawley [mailto:peter.brawley@stripped]
> Sent: February 22, 2012 11:07 AM
> To: Steven Staples; mysql@stripped
> Subject: Re: MySQL Session Variables with PHP
> On 2/22/2012 9:47 AM, Steven Staples wrote:
> > Good [insert time of day here] all!
> > I am trying to reorder my auto-inc field in my database, and I have
> > successfully done it with my "front end" that I use (SQLYog) with the
> > following code:
> > SET @var_name = 0;
> > UPDATE `my_database`.`my_table` SET `id` = (@var_name := @var_name +1);
> > Now, when I try this within PHP... I can't get it to work at all. I
> > that the SET is the issue, but I am not 100% sure.
> > I use the PEAR MDB2 class, and I have tried it in 1 statement, but it
> > failed, and I tried it with 2 statements, it didn't puke on it, but it
> > didn't work either.
> > <?php
> > # db connection is already set up #
> > echo $db->exec('SET @var_name = 0;')
> > echo '<br />';
> > echo $db->exec('UPDATE `my_database`.`my_table` SET `id` =
> > (@var_name:= @ var_name +1);');
> > exit;
> > ?>
> > Does anyone know how I can do this within PHP? Worst case scenario, is
> > I just write a php shell() command instead, but I would rather avoid
> > at all possible.
> The manual warns us not to rely on repeat user var assignments, but your
> approach works for me:
> $conn=mysql_connect( ... );
> mysql_query( "drop table if exists t" ) or exit(mysql_error());
> mysql_query( "create table t (id int)" ) or exit(mysql_error());
> for( $i=0; $i<10; $i++ ) mysql_query( "insert into t values(0)" ) or
> mysql_query( "set @var=0" ) or exit(mysql_error());
> mysql_query( "update t set id=(@var:=@var+1)" ) or exit(mysql_error());
> $res = mysql_query( "select id from t" ) or exit(mysql_error());
> while( $row = mysql_fetch_row( $res )) echo $row, " ";
> Output: 1 2 3 4 5 6 7 8 9 10
I feel like a TOTAL newb here...
If you look at my php example, I forgot the ; at the end of the first db
query... so it failed out silently (my php errors are off, changed that too)
Now it works... lol
As for why I want to do this? I have a table that I constantly add, and
remove items from, and I do it by looking up, and then deleting them (it is
a long story/process). Anyways, the script stops every 8 hours, and
restarts. So what I want to do, is reset all the auto-inc counters back to
starting at 1, so that they don't get too large and out of control. I
don't need to reference the ID's anywhere else, just when I go through each
iteration. I know that this *could* be bad for most databases/tables, but
in my case, it is not going to be an issue.
Thanks, and sorry for my ID10T error, since it works just fine!