PHP Update Query While Loop - php

Question

So I have 2 tables named accounts and tblDataNumbers. The accounts table has a sponsorID field while the tblDataNumbers table has xsponsorID field. So first, this is the code:
for ($x = 501; $x <= 1061; $x++) {
$data = $conn->query("SELECT * FROM tblDataNumbers WHERE tableID = $x");
foreach ($data as $d) {
$xsponsorID = $d['xsponsorID'];
}
$checkSponsor = $conn->query("SELECT * FROM accounts WHERE sponsorID = '".$xsponsorID."' ");
if(count($checkSponsor) > 0) {
$xsid = $xsponsorID;
} else {
$xsid = "";
}
$stmt = $conn->prepare('UPDATE tblDataNumbers SET xsponsorID=:xsponsorID WHERE tableID=:x');
$stmt->execute(array(
':xsponsorID' => $xsid,
':x' => $x
));
}
The code above will check if the $xsponsorID is existing on the sponsorID field of the accounts table. If yes, it will set $xsid to the same value which is $xsponsorID and if not, it will be set to blank or "". When I run the code, nothing happens. There are lots of numbers in the xsponsorID field of the tblDataNumbersthat table that is not present in the sponsorID field of the accounts table so basically something should be set to blank but not even one.
What I wanted to happen with this is to repeat the code inside from row 501 to 1061 of table tblDataNumbers but nothing happens. Is there something wrong with my code? Thank you.

Answer 1

I don't know if this is what you are attempting but that could potentially kill the server for a while as there will be 560 x records (from 1st query ) = lots!
I think there must be a neater solution that does the work in one query - I shall look at the queries in detail to see if there is a solution.
for( $x = 501; $x <= 1061; $x++ ) {
$data = $conn->query("SELECT * FROM tblDataNumbers WHERE tableID = $x");
/* This loop will only ever get one result..
foreach( $data as $d ){
$xsponsorID = $d['xsponsorID'];
}
*/
foreach( $data as $d ){
$xsponsorID = $d['xsponsorID'];
$checkSponsor = $conn->query("SELECT * FROM accounts WHERE sponsorID = '".$xsponsorID."' ");
$xsid=( count( $checkSponsor ) > 0 ) ? $xsponsorID : '';
$stmt = $conn->prepare('UPDATE `tblDataNumbers` SET `xsponsorID`=:xsponsorID WHERE `tableID`=:x;');
$stmt->execute(array(
':xsponsorID' => $xsid,
':x' => $x
));
}
}
After looking at this again and reading your comments I wondered if something along the lines of the following might do the trick. I created a new database with the same two named tables and populated some test data ( though I do not know if it resembles your own data ) and used the following as a test within heidi ( mysql gui app )
set #tblid=1;
update `tblDataNumbers` t set t.`xsponsorID`=(
case
when ( t.`xsponsorID` not in ( select `sponsorID` from `accounts` ) ) then
null
else
t.`xsponsorID`
end
)
where t.`tableID`=#tblid;
Clearly this updates a record where the tableID is equal to the #tblid var only. However, to update all the records that match the criteria, remove the where clause and it will apply the NULL value to any record in the tblDataNumbers table that does not have a corresponding sponsorID in the accounts table. Before running this I would strongly advise making a backup of your data though!!!!
Without the mysql variable the query becomes the following and means you would not need the loops.
update `tblDataNumbers` t set t.`xsponsorID`=(
case
when ( t.`xsponsorID` not in ( select `sponsorID` from `accounts` ) ) then
null
else
t.`xsponsorID`
end
)
If it is important to update the records only between 501 and 1061 then you could add a where clause such as:-
where t.`tableID` between 501 and 1061

Answer 2

Thanks to #RamRaider, managed to fix it by adding a single line and removing the count() function.
for( $x = 501; $x <= 1061; $x++ ) {
$data = $conn->query("SELECT * FROM tblDataNumbers WHERE tableID = $x");
foreach( $data as $d ){
$xsponsorID = $d['xsponsorID'];
$checkSponsor = $conn->query("SELECT * FROM accounts WHERE sponsorID = '".$xsponsorID."' ");
$row = $checkSponsor->fetch(PDO::FETCH_ASSOC); //I forgot this line
$xsid=( $row > 0 ) ? $xsponsorID : '';
$stmt = $conn->prepare('UPDATE `tblDataNumbers` SET `xsponsorID`=:xsponsorID WHERE `tableID`=:x;');
$stmt->execute(array(
':xsponsorID' => $xsid,
':x' => $x
));
}
}