我有一个表，它的名称是'specialization'数据库名称是'hackathon'在表内它有一行和8列“id”“name”“soft_dev”“Data_analytics”“DB_manager”“sys_engineer”“research”“networks_admin”第一行数据是“5，gourav，59. 7，72. 6，73. 87，59. 14，43. 14，50.74”现在这些分别是值。I am on $row ['Data_analytics']表示我现在可以访问值72.6。我想找出存储该值的列的名称，就像名称是“Data_analytics”一样。我想返回该值，我们可以怎么做

<?php
$value = 72.6; // the value you have access to
// Connect to the database
$db = new mysqli("localhost", "root", "", "hackathon");
// Prepare the query
$query = "SELECT COLUMN_NAME FROM information_schema.columns 
WHERE table_name = 'specialization' AND table_schema = 'hackathon' 
AND (column_name LIKE 'soft_dev' OR column_name LIKE 'Data_analytics' OR column_name LIKE 'DB_manager' OR column_name LIKE 'sys_engineer' OR column_name LIKE 'research' OR column_name LIKE 'networks_admin') 
AND EXISTS (SELECT * FROM specialization WHERE Data_analytics = ?)";
$stmt = $db->prepare($query);
$stmt->bind_param("d", $value);
$stmt->execute();
// Retrieve the result
$result = $stmt->get_result();
$row = $result->fetch_assoc();
// Get the column name
$column_name = $row['COLUMN_NAME'];
echo "The value " . $value . " is stored in the column " . $column_name;
$stmt->close();
$db->close();
?>

当我打印列名称时，它给出了一个错误，说试图访问空变量或空值