imposible query?

[pablo_ar]

I want to compera a row with a previous row and select only the ones where the diference between the values is 1.
Is that posible, four days trying.........nothing.

Thanks in advance.

[weekender]

why do it in one query? why not load all (or a subset) into an array and use php to mark those which fit the criteria? depending on the frequency that you need to do this, you could cache the results if required...

[pablo_ar]

I had thinking on an array, but i think that could be done in one query...... 'cause i will have 3.000.000 plus records.......
They will be filtered but.........could be a big result set.
Any more ideas.

Thanks.

[dnszero]

It should be possible to eventually do something like this, but....

When you run into a problem like this, it's generally wise to reconsider your database design. The most obvious rewrite that comes to mind, would be to do the comparison upon INSERT or UPDATE and store the value in the current the row. I think this would be far more efficient (and far easier) than trying to work a comparative dynamic querry. Another option might be to use a second table keyed off the first to record whatever info it is you need. This could be a streamlined table optimized for a given task or something.

In any event, I think it's definately possible to do what you ask, but I think you'll be happier if you can find a different method of accomplishing your goals.

[TTT]

$q = "select id from table"

$resArray = array();
$counter = 0;
while($rs = mysql_fetch_row($q)) {
if($counter != 0) {
if($resArray[$counter-1] != $rs[0]) {
array_push($resArray,$rs[0]);
}
}

$counter++;

}