为什么会出现错误：查询为空？

Question

I am getting this error when I try to use the following code! I don't understand the reason. I assume its something to do with the UPDATE but i dont get what it is!

<?php
$con = mysql_connect("localhost","","");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("", $con);

mysql_query("UPDATE pages SET pagebody = 'firstname'");

if (!mysql_query($sql,$con))
  {
  die('Error: ' . mysql_error());
  }
echo "1 record added";

mysql_close($con);
?>

Answer 1

You don't select database here mysql_select_db("[db name]", $con); . And another thing, are you planning to update all entries in the pages table? Because you don't have a WHERE clause. The comments here have their points though.