PHP 7.1.20 Released

mysqli::$insert_id

mysqli_insert_id

(PHP 5, PHP 7)

mysqli::$insert_id -- mysqli_insert_id返回最后一条插入语句产生的自增 ID

说明

面向对象风格

过程化风格

mixed mysqli_insert_id ( mysqli $link )

mysqli_insert_id() 函数返回最后一个 SQL 语句(通常是 INSERT 语句) 所操作的表中设置为 AUTO_INCREMENT 的列的值。 如果最后一个 SQL 语句不是 INSERT 或者 UPDATE 语句, 或者所操作的表中没有设置为 AUTO_INCREMENT 的列, 返回值为 0。

Note:

如果在所执行的 INSERT 或者 UPDATE 语句中使用了数据库函数 LAST_INSERT_ID()。 有可能会影响 mysqli_insert_id() 函数的返回值。

参数

link

仅以过程化样式:由mysqli_connect()mysqli_init() 返回的链接标识。

返回值

最后一条 SQL(INSERT 或者 UPDATE)所操作的表中设置为 AUTO_INCREMENT 属性的列的值。 如果指定的连接上尚未执行 SQL 语句,或者最后一条 SQL 语句所操作的表中没有设为 AUTO_INCREMENT 的列,返回 0。

Note:

如果返回值超出了 php 允许的最大整数值, mysqli_insert_id() 函数会以字符串形式返回这个值。

范例

Example #1 $mysqli->insert_id 例程

面向对象风格

<?php
$mysqli 
= new mysqli("localhost""my_user""my_password""world");

/* 检查连接 */
if (mysqli_connect_errno()) {
    
printf("Connect failed: %s\n"mysqli_connect_error());
    exit();
}

$mysqli->query("CREATE TABLE myCity LIKE City");

$query "INSERT INTO myCity VALUES (NULL, 'Stuttgart', 'DEU', 'Stuttgart', 617000)";
$mysqli->query($query);

printf ("New Record has id %d.\n"$mysqli->insert_id);

/* 删除表 */
$mysqli->query("DROP TABLE myCity");

/* 关闭连接 */
$mysqli->close();
?>

过程化风格

<?php
$link 
mysqli_connect("localhost""my_user""my_password""world");

/* 检查连接 */
if (mysqli_connect_errno()) {
    
printf("Connect failed: %s\n"mysqli_connect_error());
    exit();
}

mysqli_query($link"CREATE TABLE myCity LIKE City");

$query "INSERT INTO myCity VALUES (NULL, 'Stuttgart', 'DEU', 'Stuttgart', 617000)";
mysqli_query($link$query);

printf ("New Record has id %d.\n"mysqli_insert_id($link));

/* 删除表 */
mysqli_query($link"DROP TABLE myCity");

/* 关闭连接 */
mysqli_close($link);
?>

以上例程会输出:

New Record has id 1.
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User Contributed Notes 8 notes

up
45
will at phpfever dot com
12 years ago
I have received many statements that the insert_id property has a bug because it "works sometimes".  Keep in mind that when using the OOP approach, the actual instantiation of the mysqli class will hold the insert_id. 

The following code will return nothing.
<?php
$mysqli
= new mysqli('host','user','pass','db');
if (
$result = $mysqli->query("INSERT INTO t (field) VALUES ('value');")) {
   echo
'The ID is: '.$result->insert_id;
}
?>

This is because the insert_id property doesn't belong to the result, but rather the actual mysqli class.  This would work:

<?php
$mysqli
= new mysqli('host','user','pass','db');
if (
$result = $mysqli->query("INSERT INTO t (field) VALUES ('value');")) {
   echo
'The ID is: '.$mysqli->insert_id;
}
?>
up
3
drburnett at mail dot com
1 year ago
msqli_insert_id();
This seems to return that last id entered.
BUT,  if you have multiple users running the same code, depending on the server or processor I have seen it return the wrong id.

Test Case:
Two users added an item to their list.
I have had a few times where the id was the id from the other user.
This is very very rare and it only happens on my test server and not my main server.

I am guessing it is because of multicores (maybe hyperthreading) or how the operating system handles multi-threads.

It is rare, but it happens.
up
6
bert at nospam thinc dot nl
10 years ago
Watch out for the oo-style use of $db->insert_id. When the insert_id exceeds 2^31 (2147483648) fetching the insert id renders a wrong, too large number. You better use the procedural mysqli_insert_id( $db ) instead.

[EDIT by danbrown AT php DOT net: This is another prime example of the limits of 32-bit signed integers.]
up
6
alan at commondream dot net
13 years ago
I was having problems with getting the inserted id, and did a bit of testing. It ended up that if you commit a transaction before getting the last inserted id, it returns 0 every time, but if you get the last inserted id before committing the transaction, you get the correct value.
up
0
Nick Baicoianu
11 years ago
When running extended inserts on a table with an AUTO_INCREMENT field, the value of mysqli_insert_id() will equal the value of the *first* row inserted, not the last, as you might expect.

<?
//mytable has an auto_increment field
$db->query("INSERT INTO mytable (field1,field2,field3) VALUES ('val1','val2','val3'),
('val1','val2','val3'),
('val1','val2','val3')");

echo $db->insert_id; //will echo the id of the FIRST row inserted
?>
up
-2
owenzx at gmail dot com
4 years ago
The example is lack of insert_id in multi_query. Here is my example:
Assuming you have a new test_db in mysql like this:

create database if not exists test_db;
use test_db;
create table user_info (_id serial, name varchar(100) not null);
create table house_info (_id serial, address varchar(100) not null);

Then you run a php file like this:

<?php
define
('SERVER', '127.0.01');
define('MYSQL_USER', 'your_user_name');
define('MYSQL_PASSWORD', 'your_password');

$db = new mysqli(SERVER, MYSQL_USER, MYSQL_PASSWORD, "test_db", 3306);
if (
$db->connect_errno)
  echo
"create db failed, error is ", $db->connect_error;
else {
 
$sql = "insert into user_info "
   
. "(name) values "
   
. "('owen'), ('john'), ('lily')";
  if (!
$result = $db->query($sql))
    echo
"insert failed, error: ", $db->error;
  else
    echo
"last insert id in query is ", $db->insert_id, "\n";
 
$sql = "insert into user_info"
   
. "(name) values "
   
. "('jim');";
 
$sql .= "insert into house_info "
   
. "(address) values "
   
. "('shenyang')";
  if (!
$db->multi_query($sql))
    echo
"insert failed in multi_query, error: ", $db->error;
  else {
    echo
"last insert id in first multi_query is ", $db->insert_id, "\n";
    if (
$db->more_results() && $db->next_result())
      echo
"last insert id in second multi_query is ", $db->insert_id, "\n";
    else
      echo
"insert failed in multi_query, second query error is ", $db->error;
  }
 
$db->close();
}
?>

You will get output like this:

last insert id in query is 1
last insert id in first multi_query is 4
last insert id in second multi_query is 1

Conclusion:
1 insert_id works in multi_query
2 insert_id is the first id mysql has used if you have insert multi values
up
-5
Himadri himadri dot s dot roy at ansysoft dot com
2 years ago
Hi  mail at nikha dot org,

I must say your way of getting the key is not correct. Consider a multi user situation where everyone is registering and you are returning their id. Let's say A, B and C are registering at the same time.

Regards
Himadri
up
-50
mail at nikha dot org
4 years ago
Hi Dears,

msqli_insert_id() simply does not ALWAYS return the correct value.

Use it only, if you performed some inserts just before. Then you get what you want.

In all other cases: may be, may be not.

I never found out why and why not.

I'm now performing a query like this:
SELECT MAX(`id`) FROM `table`

(by calling mysqli_query() in procedural style, for OO may be similar.)

It' s simple and  reliable - if you have set your id colum to "auto-increment". (if not: hm, why not??);
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