foreach with mysqli_multi_query issue - php

Question

I have the below code which works fine and updates each record contained in the array:
$check_list = isset($_POST['check_list']) ? $_POST['check_list'] : array();
foreach($check_list as $check_list) {
$query = "UPDATE `stock` SET `signature_id` = 0,
user_id = 0,
`status_id` = 1
WHERE `id` = '$check_list'";
$result = mysqli_query($conn, $query);
I now need it to execute multiple queries for each result in the array so I have changed the code to the following using mysqli_multi_query:
$check_list = isset($_POST['check_list']) ? $_POST['check_list'] : array();
foreach($check_list as $check_list) {
$query = "UPDATE `stock` SET `signature_id` = 0,
user_id = 0,
`status_id` = 1
WHERE `id` = '$check_list';
INSERT INTO `returned`
(`id`, `stock_id`, `signature_id`,
`user_id`, `timestamp`)
VALUES ('','$check_list','$id',
'$user_id',now())";
$result = mysqli_multi_query($conn, $query);
But it now only executes one UPDATE and one INSERT for the first record in the array, and ignores the others

Answer 1

#RiggsFolly is giving the best advice about prepared parameterised statements and transactions due to re-usability and security, but if you want/need to stay with mysqli_multi_query, (because you don't want to transition to a new querying process mid-project or because it is otherwise unappealing to you) here is how mysqli_multi_query can serve you:
Query Combination:
If the SET values stay the same and only the id's are different, all UPDATE queries can be merged into a single query. If the values are static you can use implode(), if not you can chose between using a (verbose/ugly) CASE statement in the SET clause of a single query, or create multiple UPDATE queries as in your original post.
$queries="UPDATE `stock` SET `signature_id`=0,`user_id`=0,`status_id`=1 WHERE `id` IN (".implode(',',$check_list).");";
Likewise with the INSERT queries, they can all be merged into one statement with implode() or a foreach loop that only extends the VALUE portion.
$queries.="INSERT INTO `returned` (`stock_id`,`signature_id`,`user_id`,`timestamp`) VALUES ('".implode("','$id','$user_id',now()),('",$check_list)."','$id','$user_id',now());";
or
$queries.="INSERT INTO `returned` (`stock_id`,`signature_id`,`user_id`,`timestamp`) VALUES ";
foreach($check_list as $k=>$check_list){
// manipulate $id and $user_id as needed
$queries.=($k==0?"":",")."('$check_list','$id','$user_id',now())";
}
Failure Awareness:
If you don't need any kind of indication of success then a one-liner will do (keep this outside of any loops of course):
mysqli_multi_query($conn,$queries)
otherwise, you'll need a slightly larger block of code:
if(mysqli_multi_query($conn,$queries)){
do{
echo "<br>Rows = ",mysqli_affected_rows($conn);
} while(mysqli_more_results($conn) && mysqli_next_result($conn));
}
if($mysqli_error=mysqli_error($conn)){
echo "<br>Syntax Error: $mysqli_error";
}
I have tested my solution using implode() for both queries and was successful using:
$check_list=array(1,3,5,6,10,11);
and a database setup of:
CREATE TABLE `stock` (
id int(10) NOT NULL AUTO_INCREMENT,
signature_id int(10) NOT NULL,
user_id int(10) NOT NULL,
status_id int(10) NOT NULL,
PRIMARY KEY (id)
);
CREATE TABLE `returned` (
id int(10) NOT NULL AUTO_INCREMENT,
stock_id int(10) NOT NULL,
signature_id int(10) NOT NULL,
user_id int(10) NOT NULL,
`timestamp` datetime NOT NULL,
PRIMARY KEY (id)
);
/* Declaring your `id` columns with AUTO_INCREMENT means you can omit them from your INSERT query. */
/* Depending on your mysql version, creating a default datetime for `timestamp` may be possible which then would permit omitting `timestamp` from your INSERT query too. */
INSERT INTO `stock` (`signature_id`,`user_id`,`status_id`) VALUES
(1,1,1),
(2,2,2),
(3,3,3),
(4,4,4),
(5,5,5),
(6,6,6),
(7,7,7),
(8,8,8),
(9,9,9),
(10,10,10),
(11,11,11),
(12,12,12);
The built query looks like this:
UPDATE `stock` SET `signature_id`=0,`user_id`=0,`status_id`=1 WHERE `id` IN (1,3,5,6,10,11);INSERT INTO `returned` (`stock_id`,`signature_id`,`user_id`,`timestamp`) VALUES ('1','','',now()),('3','','',now()),('5','','',now()),('6','','',now()),('10','','',now()),('11','','',now());