Get latest row of database and echo id

Question

I just need to get the latest row of a database and echo the id of that row. I can't seem to get it to work. I just get an "Internal Server Error" when I try to load the php page.

<?php 
include ("connection.php");
$query = mysql_query('SELECT id FROM timestamp ORDER BY id DESC LIMIT 1');
        $result = mysqli_query($link, $query);
        $row = mysqli_fetch_array($result);
        echo $row['id'];
?>

Answer 1

Firstly, you're using two different MySQL functions to query with:

$query = mysql_query('SELECT id FROM timestamp ORDER BY id DESC LIMIT 1');
         ^^^^^^^^^^^
        $result = mysqli_query($link, $query);
                  ^^^^^^^^^^^^

and we have no idea what MySQL API you're using to connect with.

Different MySQL APIs do not intermix. You need to use the same one from connection to query.

Remove mysql_query from your code and the brackets are not needed.

$query = 'SELECT id FROM timestamp ORDER BY id DESC LIMIT 1';
        $result = mysqli_query($link, $query);

and assuming a (successful) mysqli_ connection.

• Ref: http://php.net/manual/en/function.mysqli-connect.php

Also add or die(mysqli_error($link)) to mysqli_query() should there be any errors in your query.

Additional references:

• http://php.net/manual/en/mysqlinfo.api.choosing.php
• Can I mix MySQL APIs in PHP?

You can also make use of mysqli_insert_id()

• http://php.net/manual/en/mysqli.insert-id.php

Returns the auto generated id used in the last query

---

Footnotes:

Anyone asking about timestamp. That isn't a MySQL "reserved" word, but a "keyword". Those are two different animals altogether.

• https://dev.mysql.com/doc/refman/5.5/en/keywords.html

There is no (R) next to it TIMESTAMP, as opposed to say TINYBLOB (R) for example.

Therefore, ticks are not required to be wrapped around their table name.

Answer 2

Why do you use "mysql"? mysql_ functions are now deprecated. You should use "mysqli" or PDO.mysqli supported same function like "mysql"

Example how to use mysqli

<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

mysqli_query($con,"INSERT INTO Persons (FirstName,LastName,Age)
VALUES ('Glenn','Quagmire',33)");

// Print auto-generated id
echo "New record has id: " . **mysqli_insert_id($con)**;

mysqli_close($con);
?>

mysqli_insert_id($con) using this you can get last inserted id from database and using this id you can get a row. but if you still need to use mysql then you may use this function mysql_insert_id(); you can get last inserted row id see example below

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

// it print last inserted id 
printf("Last inserted record has id %d\n", mysql_insert_id());
?>

reffer to this http://php.net/manual/en/function.mysql-insert-id.php

and using that is also fetch last inserted row

Answer 3

OOP Style-

<?php 
include ("connection.php");
$query = new mysqli_query('SELECT id FROM timestamp ORDER BY id DESC LIMIT 1');
    $result = new mysqli_query($link, $query);
     $row = new mysqli_fetch_array($result);
    echo $row['id'];
   ?>

Answer 4

try with this code. you have to use "mysqli_query" instead "mysql_query."

<?php 
include ("connection.php"); //contains mysqli_connect information (the $mysqli variable)

$query = mysqli_query('SELECT id FROM timestamp ORDER BY id DESC LIMIT 1');
        $result = mysqli_query($mysqli, $query);
        $row = mysqli_fetch_array($result);
        echo $row['id'];
?>

thanks.

Answer 5

use below query instead

select * from (SELECT id FROM timestamp ORDER BY id DESC) abc limit 1