mysql_error

(PHP 4, PHP 5, PECL mysql:1.0)

mysql_error — 直近に実行された MySQL 操作のエラーメッセージを返す

説明

string mysql_error ([ resource $link_identifier ] )

直近の MySQL 関数からのエラー文字列を返します。 MySQL データベースバックエンドから返ってくるエラーは、警告を発生しません。代わりに mysql_error() を用いてエラー文字列を取得してください。この関数が返すのは、直近に実行された MySQL 関数（mysql_error() と mysql_errno() は除く）のエラー文字列だけであることに注意しましょう。この関数を利用するなら、別の MySQL 関数をコールする前に値を調べることを忘れないようにしましょう。

パラメータ

link_identifier: MySQL 接続。指定されない場合、mysql_connect() により直近にオープンされたリンクが指定されたと仮定されます。そのようなリンクがない場合、引数を指定せずに mysql_connect() がコールした時と同様にリンクを確立します。リンクが見付からない、または、確立できない場合、 E_WARNING レベルのエラーが生成されます。

返り値

直近の MySQL 関数からのエラー文字列を返します。エラーが発生していない場合には、'' (空文字列) を返します。

例

例1 mysql_error() の例


<?php
$link = mysql_connect("localhost", "mysql_user", "mysql_password");

mysql_select_db("nonexistentdb", $link);
echo mysql_errno($link) . ": " . mysql_error($link). "\n";

mysql_select_db("kossu", $link);
mysql_query("SELECT * FROM nonexistenttable", $link);
echo mysql_errno($link) . ": " . mysql_error($link) . "\n";
?>

上の例の出力は、たとえば以下のようになります。

1049: Unknown database 'nonexistentdb'
1146: Table 'kossu.nonexistenttable' doesn't exist

参考

mysql_escape_string

mysql_errno

Last updated: Fri, 18 Jul 2008

add a note User Contributed Notes
mysql_error

Gianluigi_Zanettini-MegaLab.it
25-May-2007 03:50


A friend of mine proposed a great solution.



<?php

$old_track = ini_set('track_errors', '1');



.....



        if ($this->db_handle!=FALSE && $db_selection_status!=FALSE)

            {

            $this->connected=1;

            ini_set('track_errors', $old_track);

            }

        else

            {

            $this->connected=-1;

            $mysql_warning=$php_errormsg;

            ini_set('track_errors', $old_track);

            throw new mysql_cns_exception(1, $mysql_warning . " " . mysql_error());

            }

?>

Gianluigi_Zanettini-MegaLab.it
25-May-2007 01:20


"Errors coming back from the MySQL database backend no longer issue warnings." Please note, you have an error/bug here. In fact, MySQL 5.1 with PHP 5.2:



Warning: mysql_connect() [function.mysql-connect]: Unknown MySQL server host 'locallllllhost' (11001)



That's a warning, which is not trapped by mysql_error()!

phpnet at robzazueta dot com
23-Jan-2007 11:14


This is a big one - As of MySQL 4.1 and above, apparently, the way passwords are hashed has changed. PHP 4.x is not compatible with this change, though PHP 5.0 is. I'm still using the 4.x series for various compatibility reasons, so when I set up MySQL 5.0.x on IIS 6.0 running PHP 4.4.4 I was surpised to get this error from mysql_error():



MYSQL: Client does not support authentication protocol requested by server; consider upgrading MySQL client 



According to the MySQL site (http://dev.mysql.com/doc/refman/5.0/en/old-client.html) the best fix for this is to use the OLD_PASSWORD() function for your mysql DB user. You can reset it by issuing to MySQL:



Set PASSWORD for 'user'@'host' = OLD_PASSWORD('password');



This saved my hide.

l dot poot at twing dot nl
12-Jul-2006 05:38


When creating large applications it's quite handy to create a custom function for handling queries. Just include this function in every script. And use db_query(in this example) instead of mysql_query.



This example prompts an error in debugmode (variable $b_debugmode ). An e-mail with the error will be sent to the site operator otherwise.



The script writes a log file in directory ( in this case /log ) as well.



The system is vulnerable when database/query information is prompted to visitors. So be sure to hide this information for visitors anytime.



Regars,



Lennart Poot

http://www.twing.nl



<?php

$b_debugmode = 1; // 0 || 1



$system_operator_mail = 'developer@company.com';

$system_from_mail = 'info@mywebsite.com';



function db_query( $query ){

  global $b_debugmode;

  

  // Perform Query

  $result = mysql_query($query);



  // Check result

  // This shows the actual query sent to MySQL, and the error. Useful for debugging.

  if (!$result) {

    if($b_debugmode){

      $message  = '<b>Invalid query:</b><br>' . mysql_error() . '<br><br>';

      $message .= '<b>Whole query:</b><br>' . $query . '<br><br>';

      die($message);

    }



    raise_error('db_query_error: ' . $message);

  }

  return $result;

}



  function raise_error( $message ){

    global $system_operator_mail, $system_from_mail;



    $serror=

    "Env:       " . $_SERVER['SERVER_NAME'] . "\r\n" .

    "timestamp: " . Date('m/d/Y H:i:s') . "\r\n" .

    "script:    " . $_SERVER['PHP_SELF'] . "\r\n" .

    "error:     " . $message ."\r\n\r\n";



    // open a log file and write error

    $fhandle = fopen( '/logs/errors'.date('Ymd').'.txt', 'a' );

    if($fhandle){

      fwrite( $fhandle, $serror );

      fclose(( $fhandle ));

     }

  

    // e-mail error to system operator

    if(!$b_debugmode)

      mail($system_operator_mail, 'error: '.$message, $serror, 'From: ' . $system_from_mail );

  }



?>

05-Jan-2005 12:53


My suggested implementation of mysql_error():





$result = mysql_query($query) or die("<b>A fatal MySQL error occured</b>.\n<br />Query: " . $query . "<br />\nError: (" . mysql_errno() . ") " . mysql_error());





This will print out something like...





A fatal MySQL error occured.


Query: SELECT * FROM table


Error: (err_no) Bla bla bla, you did everything wrong





It's very useful to see your query in order to detect problems with syntax. Most often, the output message from MySQL doesn't let you see enough of the query in the error message to let you see where your query went bad- it a missing quote, comma, or ( or ) could have occured well before the error was detected. I do -not- recomend using this procedure, however, for queries which execute on your site that are not user-specific as it has the potential to leak sensative data. Recomended use is just for debugging/building a script, and for general user-specific queries which would at the worst, leak the users own information to themself.





Good luck,





-Scott

aleczapka _at) gmx dot net
16-Jul-2004 10:05


If you want to display errors like "Access denied...", when mysql_error() returns "" and mysql_errno() returns 0, use  $php_errormsg. This Warning will be stored there.  You need to have track_errors set to true in your php.ini.



Note. There is a bug in either documentation about error_reporting() or in mysql_error() function cause manual for mysql_error(), says:  "Errors coming back from the MySQL database backend no longer issue warnings." Which is not true.

olaf at amen-online dot de
22-Jun-2004 11:08


When dealing with user input, make sure that you use

<?php

echo htmlspecialchars (mysql_error ());

?>

instead of

<?php

echo mysql_error ();

?>



Otherwise it might be possible to crack into your system by submitting data that causes the SQL query to fail and that also contains javascript commands.



Would it make sense to change the examples in the documentation for mysql_query () and for mysql_error () accordingly?

miko_il AT yahoo DOT com
11-Dec-2003 11:25


Following are error codes that may appear when you call MySQL from any host language:



http://www.mysql.com/doc/en/Error-returns.html

josh ><>
13-Oct-2003 04:26


Oops, the code in my previous post only works for queries that don't return data (INSERT, UPDATE, DELETE, etc.), this updated function should work for all types of queries (using $result = myquery($query);):



    function myquery ($query) {

        $result = mysql_query($query);

        if (mysql_errno())

            echo "MySQL error ".mysql_errno().": ".mysql_error()."\n<br>When executing:<br>\n$query\n<br>";

        return $result;

    }

scott at rocketpack dot net
25-Jul-2003 02:44


My suggested implementation of mysql_error():



$result = mysql_query($query) or die("<b>A fatal MySQL error occured</b>.\n<br />Query: " . $query . "<br />\nError: (" . mysql_errno() . ") " . mysql_error());



This will print out something like...



<b>A fatal MySQL error occured</b>.

Query: SELECT * FROM table

Error: (err_no) Bla bla bla, you did everything wrong



It's very useful to see your query in order to detect problems with syntax. Most often, the output message from MySQL doesn't let you see enough of the query in the error message to let you see where your query went bad- it a missing quote, comma, or ( or ) could have occured well before the error was detected. I do -not- recomend using this procedure, however, for queries which execute on your site that are not user-specific as it has the potential to leak sensative data. Recomended use is just for debugging/building a script, and for general user-specific queries which would at the worst, leak the users own information to themself.



Good luck,



-Scott

10-May-2001 07:03


some error can't handle. Example: 





ERROR 1044: Access denied for user: 'ituser@mail.ramon.intranet' to database 'itcom'





This error ocurrs when a intent of a sql insert of no authorized user. The results: mysql_errno = 0 and the mysql_error = "" .

add a note

mysql_escape_string

mysql_errno

Last updated: Fri, 18 Jul 2008