PHP MySQL SELECT SUM not working

Question

I did a little research in how I could total up the values of a column in MySQL and found that SELECT SUM was the best method, however I've spent hours trying to work this out and I still can't get it to work:

Here's the code:

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$result = mysqli_query('SELECT SUM(price) AS value_sum FROM xCarts_'. $useXsesh .'_sandwiches'); 
$row = mysqli_fetch_assoc($result); 
$sum = $row['value_sum'];

echo $sum;
mysqli_close($conn);

Here's the table:

Is the price column int (or something that is not text/string)? — Tom Udding
– Tom Udding, Commented Mar 19, 2017 at 8:53

hassan · Accepted Answer · 2017-03-19 09:04:09Z

you are connecting to database using OOP style, then trying to fetch your data using procedural style,

you need to convert your procedural to OOP;

this lines:

$result = mysqli_query('SELECT SUM(price) AS value_sum FROM xCarts_'. $useXsesh .'_sandwiches'); 
$row = mysqli_fetch_assoc($result); 
$sum = $row['value_sum'];

should be as follows:

$result = $conn->query('SELECT SUM(price) AS value_sum FROM xCarts_'. $useXsesh .'_sandwiches'); 
$row = $result->fetch_assoc(); 
$sum = $row['value_sum'];

if you need to keep your procedural style, connect to mysqli using the procedural style:

$conn = mysqli_connect($servername, $username, $password, $dbname);

if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

then pass your connection to mysqli_* function as follows:

$result = mysqli_query($conn, 'SELECT SUM(price) AS value_sum FROM xCarts_'. $useXsesh .'_sandwiches');
//                     ^^^^^
$row = mysqli_fetch_assoc($result); 

$sum = $row['value_sum'];

zerek · Accepted Answer · 2017-03-19 09:01:07Z

0

Your query is good. Maybe your 'id' attribute isn't a numeric type ?

answered Mar 19, 2017 at 9:01

zerek

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