php 无法 select 数据

php unable to select data

我正在尝试 select 来自 mysql 数据库的单个值。我在 phpmyadmin 中有 运行 查询,效果很好。但是当我回显 $result 时,我什么也得不到...顺便说一下,我使用 xxx 作为数据库和密码,因为我不想显示它...我的插入查询工作得很好

谢谢

<?php

//Create Connection
$servername = "localhost";
$username = "root";
$password = "xxx";
$dbname = "xxx";



//Connect
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT StartPriceUnder FROM YJ_Value";
$result = $conn->query($sql);



echo hi;
echo $result;
echo ya;

$conn->close();

?>

你必须获取你的结果,所以做这样的事情:

$row = $result->fetch_array(MYSQLI_ASSOC);

之后你可以像这样回显它:

echo $row["StartPriceUnder"];

有关 fetch_array() 的更多信息,请参阅手册:http://php.net/manual/en/mysqli-result.fetch-array.php

试试这个:

<?php
$servername = "localhost";
$username = "root";
$password = "xxx";
$dbname = "xxx";

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

$sql = "SELECT StartPriceUnder FROM YJ_Value";
$result = $conn->query($sql);

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