PHP: Unable to run same MySQL query several times - php

Question

HTML FILE:
<form method="post" action="generate.php">
Product Reference(s): (if multiple, separate by ",")<br />
<input type="text" name="project_ref" value="REF123, REF124" />
<input type="submit" value="Generate" />
</form>
PHP FILE:
<?php
$ref_array = explode(',', $_POST['project_ref']);
foreach ($ref_array as &$ref) {
// Create connection
$conn = mysqli_connect($host, $username, $password, $dbname);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
$sql = "SELECT * FROM `inventory` WHERE reference = '$ref' LIMIT 1";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
// output data of each row
while($row = mysqli_fetch_assoc($result)) {
echo "Brand: " . $row["brand"]. "<br>";
}
} else {
echo "0 results";
}
mysqli_close($conn);
}
?>
RESULTS:
Brand: Bose
0 results
But I actually wanted:
Brand: Bose
Brand: Beats
So the problem is that the MySQL query is not running for every array item. Its only executing the first item of the array.

Answer 1

Your input value has a space between the different refs: REF123, REF124
You can either explode on a comma & space:
$ref_array = explode(', ', $_POST['project_ref']);
Or trim the values:
$sql = "SELECT * FROM `inventory` WHERE reference = '" . trim($ref) . "' LIMIT 1";
It's also strongly recommended that you pass in $ref as a parameter, rather than a string literal:
http://php.net/manual/en/mysqli-stmt.bind-param.php

Answer 2

It looks like your issue is in your explode. The first value of the explode is correct the second (third, forth, etc.) will have a leading space. explode on ', ' instead of ',' or trim the results before using it.
But there are a few other things in this code. Don't create a new connection for each query, the single connection will work just reuse it. Second, use parameters or sanitize the value before you use it in the sql, this will help prevent sql injection attacks, a better way is to use PDO and use parameters. Last, change your query so that a single query returns all the results you need by using an IN clause.
<?php
$ref_array = explode(', ', $_POST['project_ref']);
$ref_IN = "";
foreach ($ref_array as $ref_val)
$ref_IN .= "'{$ref_val}', ";
$ref_IN = rtrim($ref_IN , ",");
// Create connection
$conn = mysqli_connect($host, $username, $password, $dbname);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
$sql = "SELECT * FROM `inventory` WHERE reference IN ({$ref_IN}) GROUP BY reference";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
// output data of each row
while($row = mysqli_fetch_assoc($result)) {
echo "Brand: " . $row["brand"]. "<br>";
}
} else {
echo "0 results";
}
mysqli_close($conn);
?>