PHP - 如何回显列中值的总和？

Question

例如，我有一个数据库和一张表，表里面是id，user，votes，

id = primary and auto increment

users = varchar

votes = int

我如何计算投票字段中的值并回显它？

Answer 1

试试这个，

$result = mysql_query('SELECT SUM(votes) AS value_sum FROM table_name'); 
$row = mysql_fetch_assoc($result); 
$sum = $row['value_sum'];

使用 SQLi

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

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

$sql = "SELECT SUM(votes) AS value_sum FROM table_name";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "sum is : " . $row["value_sum"];
    }
} else {
    echo "0 results";
}
$conn->close();