How to run an sql query inside another SQL query in PHP? - php

Question

How can I run a SELECT query which picks an ID which I use to delete a row in another table with that ID and later delete the row of that ID in its own table?
My code so far:
$sqel = "SELECT fldRadioCampID FROM tblradiocamp WHERE fldBestelID = '$urlIDbon' AND fldSpotnaam = '$urlDelSpotnaam'";
$result = mysql_query($link, $sqel);
if (mysql_num_rows($result) > 0) {
// output data of each row
while($row = mysql_fetch_assoc($result)) {
$sqeldelreg = "DELETE FROM tblradioregio WHERE fldRadiocampRegID=" . $row['fldRadioCampID'];
if (!mysql_query($sqeldelreg)) {
echo "Error: " . $sqeldelreg . "<br>" . mysql_error($link);
}
}
} else {
}
$sqeldel = "DELETE FROM tblradiocamp WHERE fldBestelID='$urlIDbon' AND fldSpotnaam='$urlDelSpotnaam'";
if (!mysql_query($sqeldel)) {
echo "Error: " . $sqeldel . "<br>" . mysql_error($link);

Answer 1

You can create procedure and call it once.
MYSQL
CREATE PROCEDURE `deleteRowById` (in urlDelSpotnaam varchar(64), in urlIDbon varchar(64) )
BEGIN
declare a int(11);
SELECT fldRadioCampID into a FROM tblradiocamp WHERE fldBestelID = urlIDbon AND fldSpotnaam = urlDelSpotnaam;
if a > 0 then
DELETE FROM tblradioregio WHERE fldRadiocampRegID=a;
DELETE FROM tblradiocamp WHERE fldRadioCampID=a;
END IF;
END
PHP
<?php
$sqel = "call deleteRowById('$urlDelSpotnaam','$urlIDbon')";
$result = mysql_query($link, $sqel);

Answer 2

run this query:
DELETE FROM tblradioregio
WHERE fldRadiocampRegID = (SELECT
fldRadioCampID
FROM tblradiocamp
WHERE fldBestelID = '$urlIDbon' AND fldSpotnaam = '$urlDelSpotnaam');
Note that this could also be done using a join instead of the sub-select; that's probably preferable if the subquery can return null:
DELETE FROM tblradioregio
join tblradiocamp b
on (tblradioregio.fldRadiocampRegID = b.fldRadioCampID)
WHERE b.fldBestelID = '$urlIDbon'
AND b.fldSpotnaam ='$urlDelSpotnaam';