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  1. #1
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    Finding out the highest number in an auto-incrementing table

    I have a row in a MySQL table called id, which auto-increments.

    I was wondering if anyone knows a PHP solution to find out what the highest number in the row is?

    I am thinking perhaps execute a MySQL query that will list the highest number, and then echo the result, like $row[id] in PHP?
    Last edited by FlashDancer; 01-21-2012 at 11:32 AM.

  • #2
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    PHP Code:
    /*
     * Define $server, $username, $password, $database and $table here as follows:
     *  $server = name of mysql server.
     *  $username = username for mysql account.
     *  $password = password for mysql account.
     *  $database = name of database to use.
     *  $table = name of table containing the id column.
     */

    $conn mysql_connect($server$username$password);
    mysql_query("use $database;"):
    $res mysql_query("select max(id) from $table;");
    $data mysql_fetch_array($res);
    $count $data[0];
    mysql_close($conn);

    echo 
    $count.PHP_ENDL
    Of course, you'll need to put some error checking in, but what I've posted above is the basic code to do what you want.
    Last edited by XmisterIS; 01-21-2012 at 01:10 PM.

  • #3
    Supreme Master coder! abduraooft's Avatar
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  • #4
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    You can also use:

    select id from <table> order by id desc limit 1
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  • #5
    Master Coder felgall's Avatar
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    Do you want the highest number there or do you want the one your script just inserted?

    If the latter then you want "SELECT LAST_INSERT_ID()"

    That function retrieves the last value actually inserted by the currently running copy of the script and will ignore any higher numbers inserted by someone else since you inserted yours.
    Stephen
    Learn Modern JavaScript - http://javascriptexample.net/
    Helping others to solve their computer problem at http://www.felgall.com/

    Don't forget to start your JavaScript code with "use strict"; which makes it easier to find errors in your code.


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