PDO bug

PDO-bug.php

<?php

const DB_HOST = 'localhost';
const DB_NAME = 'php_bug_test';
const DB_TABLE = 'timestamp_test';
const DB_USER = 'root';
const DB_PASSWORD = 'root';

$dbSQL = "CREATE DATABASE IF NOT EXISTS ".DB_NAME;
$combo = DB_NAME.'.'.DB_TABLE;
$tableSQL = <<<TABLE
CREATE TABLE IF NOT EXISTS $combo  (
  id int(11) NOT NULL AUTO_INCREMENT,
  value varchar(255) NOT NULL,
  dateAdded timestamp(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6) ON UPDATE CURRENT_TIMESTAMP(6),
  PRIMARY KEY ("id")
);
TABLE;

try {
   $dsn = "mysql:host=".DB_HOST;
   $db = new PDO($dsn, DB_USER, DB_PASSWORD, [
      PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
      PDO::ATTR_EMULATE_PREPARES => true
   ]);

   $dbCreateResult = $db->query($dbSQL);
   $tableCreateResult = $db->query($tableSQL);

   $query = $db->query("SELECT COUNT(*) FROM $combo");
   if ($query->fetchColumn() == 0) {
      $db->query("INSERT INTO $combo (value) VALUES ('one')");   
   }

   echo "PDO::ATTR_EMULATE_PREPARES = true:\n";
   $query = $db->query("SELECT dateAdded FROM $combo");
   echo $query->fetchColumn()."\n";

   $db = null;
   $db = new PDO($dsn, DB_USER, DB_PASSWORD, [
      PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
      PDO::ATTR_EMULATE_PREPARES => false
   ]);

   echo "PDO::ATTR_EMULATE_PREPARES = false:\n";
   $query = $db->query("SELECT dateAdded FROM $combo");
   echo $query->fetchColumn()."\n";
}
catch (PDOException $ex) {
   die($ex->getMessage()."\n");
}