mysql_insert_id

(PHP 4, PHP 5)

mysql_insert_id — Get the ID generated in the last query

Avviso

Questa enstensione deprecata da PHP 5.5.0, e sarà rimossa in futuro. Al suo posto, usare l'estensione MySQLi o PDO_MySQL. Vedere anche la guida MySQL: scelta dell'API e le FAQ relative per ulteriori informazioni. Le alternative a questa funzione includono:

Descrizione

mysql_insert_id(resource $link_identifier = NULL): int

Retrieves the ID generated for an AUTO_INCREMENT column by the previous query (usually INSERT).

Elenco dei parametri

link_identifier: La connessione MySQL. Se l'identificativo di connessione non è specificato, l'ultima connessione aperta da mysql_connect() viene assunta. Se questa connessione non è trovata, si cercherà di crearne una come se mysql_connect() fosse stata chiamata senza argomenti. Se una connessione non è trovata oppure non viene stabilita, un avviso di livello E_WARNING viene generato.

Valori restituiti

The ID generated for an AUTO_INCREMENT column by the previous query on success, 0 if the previous query does not generate an AUTO_INCREMENT value, or false if no MySQL connection was established.

Esempi

Example #1 mysql_insert_id() example

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');

mysql_query("INSERT INTO mytable (product) values ('kossu')");
printf("Last inserted record has id %d\n", mysql_insert_id());
?>

Note

Attenzione

mysql_insert_id() will convert the return type of the native MySQL C API function mysql_insert_id() to a type of long (named int in PHP). If your AUTO_INCREMENT column has a column type of BIGINT (64 bits) the conversion may result in an incorrect value. Instead, use the internal MySQL SQL function LAST_INSERT_ID() in an SQL query. For more information about PHP's maximum integer values, please see the integer documentation.

Nota:
Because mysql_insert_id() acts on the last performed query, be sure to call mysql_insert_id() immediately after the query that generates the value.

Nota:
The value of the MySQL SQL function LAST_INSERT_ID() always contains the most recently generated AUTO_INCREMENT value, and is not reset between queries.

Vedere anche:

mysql_query() - Send a MySQL query
mysql_info() - Get information about the most recent query

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User Contributed Notes 11 notes

down

Alfred Nony Mouse ¶

16 years ago

There's nothing inherently wrong with using auto-increment fields. There's also nothing wrong with the main competetive idea, which is for the database to supply a primitive sequence of non-repeating identifiers, typically integers. This is rather like which side of the road you drive on.

The bigger problem is when people don't understand what they are doing with database access. It's like driving a car without really knowing the rules of the road. Such people wind up making bad decisions without realizing it, and then, eventually, something breaks.

Databases are complex beasts, and worth taking the time to really understand. Learn about the implications and limitations of different approaches to solving problems. Then, you will be prepared to pick a solution based on what has to work.

down

foros (_AT_) anthalia.com ¶

17 years ago

Forget about using MAX to get the last inserted id. Race conditions like other users inserting between your SELECT MAX(.. and your INSERT may render your id unusable.

The WAY to get the id is by using mysql_insert_id() or the mysql SQL function LAST_INSERT_ID(). 

Take care, if using mysql_insert_id() you should provide the resource returned by the mysql_connect, not the resultset returned by mysql_query.

down

elinor dot hurst at REMOVETHIS dot gmail dot com ¶

16 years ago

I don't get all the fuss around this.

I read:
"The value of mysql_insert_id() is affected only by statements issued within the current client connection. It is not affected by statements issued by other clients."

See: http://dev.mysql.com/doc/refman/5.0/es/mysql-insert-id.html

I can't really see what's inaccurate about that.

"In the case of a multiple-row INSERT statement, mysql_insert_id() returns the first automatically generated AUTO_INCREMENT value; if no such value is generated, it returns the last last explicit value inserted into the AUTO_INCREMENT column."

I must be missing something here but why would you insert multiple rows and then only handle the last one with some favoured behaviour? You could just as well insert them one at a time and then handle each row separately with the latest id.

I can't see what's wrong with that.

However I can see what's wrong with simply using max(my_table.id_column) because of the concurrent access issues this would imply.

down

athies at gmail dot com ¶

19 years ago

Just a quick note. mysql_insert_id() does work with REPLACE.

down

bargainbatman at gmail dot com ¶

15 years ago

I thought this would be relevant to all the people using mysqli and looking for the ID after INSERT command :

<?php
function insert_join($catid, $disc_id) {
// insert a new item into the database
   $conn = db_connect();
   // insert new item
   $demande = "insert into categories_disc values ('', '".$catid."', '".$disc_id."')";
   $resultat = $conn->query($demande);
   if (!$resultat) {
     return false;
   } else {
    return $conn->insert_id; // function will now return the ID instead of true. 
}

}
?>

Then, on the other side, let us call this function as follows :

<?php
$cat_id = insert_join($catid, $disc_id);
if($cat_id !== false) {
    
        echo "<p>Category stuff was added to the database as follows : <br>";
        echo "<hr>ID de la category : ".$cat_id."</p><hr>";

        }
?>

down

-1

Anonymous ¶

18 years ago

Take care of setting an empty value for the AUTO_INCREMENT Field else you never get a value except zero returned from mysq_insert_id() ....

Ciao Ephraim

down

-2

hoangvu4000 at gmail dot com ¶

11 years ago

How to get ID of the last updated row in MySQL?

75
down vote
I've found an answer to this problem :)

by Pomyk

SET @update_id := 0;
UPDATE some_table SET row = 'value', id = (SELECT @update_id := id)
WHERE some_other_row = 'blah' LIMIT 1; 
SELECT @update_id;
EDIT by aefxx

This technique can be further expanded to retrieve the ID of every row affected by an update statement:

SET @uids := null;
UPDATE footable
   SET foo = 'bar'
 WHERE fooid > 5
   AND ( SELECT @uids := CONCAT_WS(',', fooid, @uids) );
SELECT @uids;
This will return a string with all the IDs concatenated by a colon.

(questions: 1388025  form stackoverflow)

down

-2

heiligkind at yahoo dot de ¶

18 years ago

If you insert a data row by using the ON DUPLICATE KEY UPDATE clause in an INSERT-statement, the mysql_insert_id() function will return not the same results as if you directly use LAST_INSERT_ID() in MySQL.

See the following example:

<?
   // insert a datarow, primary key is auto_increment
   // value is a unique key
   $query = "INSERT INTO test (value) VALUES ('test')";
   mysql_query( $query );

   echo 'LAST_INSERT_ID: ',
          mysql_query( "SELECT LAST_INSERT_ID()" ),
          '<br>mysql_insert_id: ',
          mysql_insert_id();

?>

This will print:

LAST_INSERT_ID: 1
mysql_insert_id: 1

In this case the function returns the same as the MySQL-Statement.
But see the insert on an existing key:

<?
   $query = "INSERT INTO test (value) 
                  VALUES ('test')
                  ON DUPLICATE KEY UPDATE value = 'test2'";
   mysql_query( $query );

   echo 'LAST_INSERT_ID: ',
          mysql_query( "SELECT LAST_INSERT_ID()" ),
          '<br>mysql_insert_id: ',
          mysql_insert_id();

?>

This will print:

LAST_INSERT_ID: 2
mysql_insert_id: 1

By using the ON DUPLICATE KEY UPDATE clause, only the old datarow will be modified, if the INSERT statement causes a duplicate entry, but the LAST_INSERT_ID() function returns the next auto_increment value for the primary key, which is by the way not set as the next auto_increment value in the database.

The mysql_insert_id() function returns the primary key of the old (and changed) data row. For me this is the right operation method, because the LAST_INSERT_ID() function returns a value which is not referenced to a data row at all.

Greets from Munich.

heiligkind

down

-2

louis at intoplay dot com ¶

17 years ago

If mysql_insert_id() returns 0 or null, check your auto increment field is not being set by your sql query, also if you have multiple db connections like I did, the solution is to create a seperate db connection for this query.

down

-2

vksgeneric at hotmail dot com ¶

24 years ago

You can't do an INSERT DELAYED and expect to get anything but zero, for it runs in a separate thread, and mysql_insert_id() is tied to the current thread.

Vlad

down

-5

dhiraj dot webdeveloper at gmail dot com ¶

7 years ago

MySQLi Procedural
//---------------------------------------------
$last_id = mysqli_insert_id($conn);

//---------------------------------------------
 <?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";

if (mysqli_query($conn, $sql)) {
    $last_id = mysqli_insert_id($conn);
    echo "New record created successfully. Last inserted ID is: " . $last_id;
} else {
    echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

mysqli_close($conn);
?>

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