  | 
 mysqli_error    (PHP 5) mysqli_error -- Returns a string description of the last error DescriptionProcedural style: string  mysqli_error ( mysqli link ) Object oriented style (property) class  mysqli {  string error } 
     The mysqli_error() function is identical to the corresponding
     mysqli_errno() function in every way, except instead of returning
     an integer error code the mysqli_error() function will return
     a string representation of the last error to occur for the database connection 
     represented by the link parameter. If no error has occured,
     this function will return an empty string.
     返回值
      A string that describes the error. An empty string if no error occurred. 
     例例子 1. Object oriented style 
<?php $mysqli = new mysqli("localhost", "my_user", "my_password", "world");
  /* check connection */ if (mysqli_connect_errno()) {     printf("Connect failed: %s\n", mysqli_connect_error());     exit(); }
  if (!$mysqli->query("SET a=1")) {     printf("Errormessage: %s\n", $mysqli->error); }
  /* close connection */ $mysqli->close(); ?>
 |  
  |  
 例子 2. Procedural style 
<?php $link = mysqli_connect("localhost", "my_user", "my_password", "world");
  /* check connection */ if (mysqli_connect_errno()) {     printf("Connect failed: %s\n", mysqli_connect_error());     exit(); }
  if (!mysqli_query($link, "SET a=1")) {     printf("Errormessage: %s\n", mysqli_error($link)); }
  /* close connection */ mysqli_close($link); ?>
 |  
  |  
 上例将输出: Errormessage: Unknown system variable 'a'  |  
 
  |   |