PHP MySQL Syntax Error on Select

Question

I am trying to Save an Email Address into my database and i am getting the following error

  include 'db.php';
  echo $email = $accounts['username'];
  $date = date ("Y-m-d H:m:s");

  $result = mysql_query("SELECT * FROM users where email = $email", $conn) or die($myQuery."<br/><br/>".mysql_error());
  $num_rows = mysql_num_rows($result);

  if ($num_rows == 0) {
    $query_string = "INSERT INTO users (id, email, created)
                                        VALUES (null, '$email', '$date')";

      if (mysql_query($query_string, $conn)) {
        echo "$name inserted<br/>";
      } else {
        die('Error: ' . mysql_error());
        echo "Error inserting $email<br/>";
      }

  } else {
    echo "$email exists<br/>";
  }

Error:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@mink7.com' at line 1

Answer 1

您应该在第一个SQL语句中引用$ email：

"SELECT * FROM users where email = '$email'"

Answer 2

marcochiesi has the right answer, but I would suggest mysql_real_escape_string to help prevent an SQL injection attack as well:

"SELECT * FROM users where email = '". mysql_real_escape_string($email)."'"

Update

FYI, if you don't put the quote's around the information you are constraining, MySQL is expecting it to be a column.