mysql_insert_id

(PHP 4, PHP 5)

mysql_insert_id — 取得上一步 INSERT 操作产生的 ID

说明

mysql_insert_id ( resource $link_identifier = ? ) : int

mysql_insert_id() 返回给定的 link_identifier 中上一步 INSERT 查询中产生的 AUTO_INCREMENT 的 ID 号。如果没有指定 link_identifier，则使用上一个打开的连接。

如果上一查询没有产生 AUTO_INCREMENT 的值，则 mysql_insert_id() 返回 0。如果需要保存该值以后使用，要确保在产生了值的查询之后立即调用 mysql_insert_id()。

Note:
MySQL 中的 SQL 函数 LAST_INSERT_ID() 总是保存着最新产生的 AUTO_INCREMENT 值，并且不会在查询语句之间被重置。

Warning

mysql_insert_id() 将 MySQL 内部的 C API 函数 mysql_insert_id() 的返回值转换成 long（PHP 中命名为 int）。如果 AUTO_INCREMENT 的列的类型是 BIGINT，则 mysql_insert_id() 返回的值将不正确。可以在 SQL 查询中用 MySQL 内部的 SQL 函数 LAST_INSERT_ID() 来替代。

Example #1 mysql_insert_id() 例子


<?php
    mysql_connect("localhost", "mysql_user", "mysql_password") or
        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());
?>

参见 mysql_query()。

User Contributed Notes

dhiraj dot webdeveloper at gmail dot com 28-Sep-2017 12:22


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);

?>

hoangvu4000 at gmail dot com 12-Jul-2013 05:09


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)

bargainbatman at gmail dot com 25-Sep-2009 06:16


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>";



        }

?>

elinor dot hurst at REMOVETHIS dot gmail dot com 08-Apr-2008 07:27


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.

Alfred Nony Mouse 23-Feb-2008 05:33


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.

louis at intoplay dot com 13-Aug-2007 07:53


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.

foros (_AT_) anthalia.com 31-Jul-2007 02:06


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.

heiligkind at yahoo dot de 14-Dec-2005 01:31


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

02-Dec-2005 10:48


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

athies at gmail dot com 21-Jul-2005 02:36


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

Steve Bond 24-Jun-2004 11:47


If you use this function after doing an INSERT ... SELECT to insert multiple rows at once, you get the autonumber ID of the *first* row added by the INSERT.



e.g. if there are 4 records in table 'init' that have column 'type' = 2

I want to add these 4 records to table 'game'

Table game has an autonumber column 'game_id' that is currently at 32.



If I do this query:



INSERT INTO game (type, players, rounds)

SELECT type, players, rounds FROM init

WHERE type = 2



Then mysql_insert_id() will return 33, not 36.

vksgeneric at hotmail dot com 09-Dec-1999 05:14


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