无法检索HTML输入值并在PHP脚本中使用

Question

我试图检索id =“ retriveRR”的输入值，并在PHP脚本中使用它来从mySQL获取特定数据

相反，我得到此错误未定义索引：retriveRR

我在<form>中没有输入字段，我需要在同一页面上使用数据

        <span class="chipContact">
          <span class="letterCircle">R</span>
          <span class="chiptext" id="retriveRR"></span>
        </span>

        <span class="chipContact">
          <span class="letterCircle">D</span>
          <span class="chiptext" id="retriveDate"></span>
        </span>

<?php

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


$getRR = $_GET['retriveRR']; // required

$sql = "SELECT general.RR, Initial_Date FROM general WHERE general.RR = '$getRR'";

//echo "<span>$row['Initial_Date']</span>";

$result = $conn->query($sql);

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

?>