[Newbie] Fetching a row based on Primary KEY value

ddlam

Hi, the following scripts get a row based on the value of the primary key but it will search all the rows.

<?PHP
$result = mysql_query("select * from guestbook2");

while ($row = mysql_fetch_array($result)) {
if($row["primaryKey"] == "1"){
echo $row["primaryKey"];
}
}
?>

Does there have an easier way to get a row by the value primary key?

Thank you for reading my post!

akillez

I'm not sure if this is what you mean but...

<?PHP
$result = mysql_query("select * from guestbook2 where primaryKey='1'");

while ($row = mysql_fetch_array($result))
echo $row;
?>

ddlam

Thx, can I use an $variable instead of actual value '1'?

The following scripts select nothing.

Is it need a special format for the $variable?

$result = mysql_query("select * from guestbook2 WHERE (gbID<$start) AND (gbID>$end)");

FMB

depends on what $start and $end contain.

$start = 1
$end = 10

there will be nothing where
gbID < 1 AND gbID > 10

i.e. check the contents of $start and $end

Your query might just have to be:

$result = mysql_query("select * from guestbook2 WHERE (gbID>". $start . ") AND (gbID<" . $end. ")");

ddlam

OIC, I deleted some record and id 3-5 become missing.

I want to use the following scripts to change the gbID to corresponding order.

mysql_query("UPDATE guestbook2 SET gbID='$i' WHERE gbID>0");

However, I have no idea to make the variable $i auto-increased by 1.

Could I made $i = 1,2,3,4,5...etc and fill them in row 1,2,3,4,5...etc?

Sxooter

Auto increment fields should never be renumbered. If holes in the sequence cause you problems, your design is deficient. the problem is that renumbering the autoinc field means you MAY wind up associated dependent records that should have been deleted with a newly renumbered record, or skewing the references from the right records to the wrong ones.

If you need a row number, create one articifially when doing the select, or create a seconday field that is NOT the PK and use that.

ddlam

Thanks a lot. That's better to cancel auto increment.