getting mysql_insert_id() while using ON DUPLICATE KEY UPDATE with PHP

Question

I've found a few answers for this using mySQL alone, but I was hoping someone could show me a way to get the ID of the last inserted or updated row of a mysql DB when using PHP to handle the inserts/updates.

Currently I have something like this, where column3 is a unique key, and there's also an id column that's an autoincremented primary key:

$query ="INSERT INTO TABLE (column1, column2, column3) VALUES (value1, value2, value3) ON DUPLICATE KEY UPDATE SET column1=value1, column2=value2, column3=value3";
mysql_query($query);

$my_id = mysql_insert_id();

$my_id is correct on INSERT, but incorrect when it's updating a row (ON DUPLICATE KEY UPDATE).

I have seen several posts with people advising that you use something like

INSERT INTO table (a) VALUES (0) ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id) 

to get a valid ID value when the ON DUPLICATE KEY is invoked-- but will this return that valid ID to the PHP mysql_insert_id() function?

Answer 1

Here's the answer, as suggested by Alexandre:

when you use the id=LAST_INSERT_ID(id) it sets the value of mysql_insert_id = the updated ID-- so your final code should look like:

<?
    $query = mysql_query("
        INSERT INTO table (column1, column2, column3) 
        VALUES (value1, value2, value3) 
        ON DUPLICATE KEY UPDATE
            column1 = value1, 
            column2 = value2, 
            column3 = value3, 
            id=LAST_INSERT_ID(id)
    ");
    $my_id = mysql_insert_id();

This will return the right value for $my_id regardless of update or insert.

Answer 2

You could check if the Query was an insert or an update ( mysql_affected_rows(); returns 1 on insert and 2 on update).

If it was an insert use mysql_insert_id, if it was an update you'd need another Query.

<?php
$query ="INSERT INTO TABLE (column1, column2, column3) VALUES (value1, value2, value3) ON DUPLICATE KEY UPDATE SET column1=value1, column2=value2, column3=value3";
mysql_query($query);
if(mysql_affected_rows() == 1) { $id = mysql_insert_id(); }
else { // select ... 
}
?>

I know it's not excatly what your looking for but it's the best i could come up with

Answer 3

Although not using mysql_insert_id() and ON DUPLICATE KEY UPDATE, alternative great way to get the value of any field when updating another found here:

UPDATE table SET id=(@tempid:=id) , .... LIMIT 1;
SELECT @tempid;

I used it having table with (id,status) 'id' primary index auto-increment, and 'status' was the field upon which update was made, but i needed to get 'id' of the updated row. This solution also proof to race conditions as mysql_insert_id().

Answer 4

This is my solution where you put the data into a single array and it's automatically duplicated/populated into the "INSERT INTO .. ON DUPLICATE UPDATE .. " query.

It's great for maintainability, and if you want you can make it a function / method too.

// save to db:

$qData = [
    "id" =>                mysql_real_escape_string($email_id),     
    "synd_id" =>           mysql_real_escape_string($synd_id),
    "campaign_id" =>       mysql_real_escape_string($campaign_id),
    "event_id" =>          mysql_real_escape_string($event_id),
    "user_id" =>           mysql_real_escape_string($user_id),
    "campaign_name" =>     mysql_real_escape_string($campaign_name), 
    "subject" =>           mysql_real_escape_string($subject),
    "from_name"=>          mysql_real_escape_string($from_name),
    "from_email"=>         mysql_real_escape_string($from),
    "content"=>            mysql_real_escape_string($html),
    "link_to_template" =>  mysql_real_escape_string($hash),
    "ext_campaign_id" =>   mysql_real_escape_string($ext_campaign_id),
    "ext_list_id"=>        mysql_real_escape_string($ext_list_id),
];


$q = "INSERT INTO email_campaigns (".
  // i.e create a string like `id`, `synd_id`, `campaign_id`..  with linebreaks for readability
  implode(", \n", array_map(function($k){ return "`$k`"; }, array_keys($qData)))
.")
VALUES (".
  // i.e '20', '532', '600' .. 
  implode(", \n", array_map(function($v){ return "'$v'"; }, array_values($qData)))
." )  ON DUPLICATE KEY UPDATE ".
  // i.e `synd_id`='532', `campaign_id`='600' ... 
  // id & link_to_template table keys are excluded based on the array below
  implode(", \n", array_filter(array_map(function($k, $v){ if(!in_array($k, ['id', 'link_to_template']) ) return "`$k`='$v'" ; }, array_keys($qData), array_values($qData))))  ;