This code was to create a simple database with a table and add records with the following. toIm having trouble with the 'id' auto_increment.

  <?php

$con=mysqli_connect("localhost","root","distortion","my_databs");

// Check connection

if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

// Create table

$sql="CREATE TABLE empl(ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY ,FirstName CHAR(30),LastName CHAR(30), Age INT)";


// Execute query

if (mysqli_query($con,$sql)) {
  echo "Table persons created successfully";
} else {
 echo "Error creating table: " . mysqli_error($con);
}


// escape variables for security


$firstname  = mysqli_real_escape_string($con, $_POST['firstname']);
$lastname   = mysqli_real_escape_string($con, $_POST['lastname']);
$age        = mysqli_real_escape_string($con, $_POST['age']);


$sql="INSERT INTO Empl (ID ,FirstName, LastName, Age )
VALUES ( NULL,'$firstname', '$lastname', '$age')";


if (!mysqli_query($con,$sql)) {

 die( 'Error:' . mysqli_error($con));

}
echo"<br>";
echo " -> 1 record added";

I think it should be:

CREATE TABLE empl (
    ID INT NOT NULL AUTO_INCREMENT,
    FirstName CHAR(30),
    LastName CHAR(30), 
    Age INT,
    PRIMARY KEY (id)
)

Thanks for the comment,its both the same.
ignore the ending of the php..
"?>"...

Ok, wasn't sure, so the error is in the insert query?

Can you echo $sql and show what gets executed here?

can i just post the entire program right here?

You can, if it's relevant. I still need to know the query you are executing, the code doesn't show that.

<?php

$con=mysqli_connect("localhost","root","distortion","my_databs");

// Check connection

if (mysqli_connect_errno()) {
 echo "Failed to connect to MySQL: " . mysqli_connect_error();
}



// Create table

$sql="CREATE TABLE empl( FirstName CHAR(30),LastName CHAR(30), Age INT)";


// Execute query

if (mysqli_query($con,$sql)) {
 echo "Table persons created successfully";
} else {
 echo "Error creating table: " . mysqli_error($con);
}


// escape variables for security


$firstname  = mysqli_real_escape_string($con, $_POST['firstname']);
$lastname   = mysqli_real_escape_string($con, $_POST['lastname']);
$age        = mysqli_real_escape_string($con, $_POST['age']);


$sql="INSERT INTO Empl (FirstName, LastName, Age )
VALUES ( '$firstname', '$lastname', '$age')";


if (!mysqli_query($con,$sql)) {

  die( 'Error:' . mysqli_error($con));

 }

echo " -> 1 record added";

 // Display In A Table


$result = mysqli_query( $con , " SELECT * FROM Empl " );

echo "<table border='5'>
 <tr>

<th> Firstname </th>
<th> Lastname  </th>
<th> Age       </th>

 </tr>";



while($row = mysqli_fetch_array($result)) {
 echo "<tr>";

 echo "<td>" . $row['FirstName'] .  "</td>";
echo "<td>" . $row['LastName'] .   "</td>";
 echo "<td>" . $row['Age'].         "</td>";

 echo "</tr>";
}


echo "</table>";


  mysqli_close($con);

 ?>

This code is linked to another(the above code is names as "insert.php"):

<!DOCTYPE html>
<html>
<body>

<div id= "container" style "width:500px">
<div id="header" style="background-color:#FFA500;">
<h1 style="margin-bottom:0;">
<h1  style="text-align:center;"><u>Employee Details</u></h1></h1></div>



<form action="insert.php" method="post">
<h3 style="text-align:center;">
<br>First Name:    <input type="text" name="firstname">
<br>Last Name:     <input type="text" name="lastname">
<br>Age:           <input type="text" name="age">
<br>               <input type="submit" value = "Save">
</form>



</div>
</body>
 </html>

My five cents are that the general rule of thumb with auto increment fields is that you leave them out of your insert statement, otherwise you are actually saying you want that primary key to be null, which it can't be as per your create statement.

On testing, use your current code with the table statement suggested by pritaeas, you should be able to get the results you were aiming for. Don't include the auto increment field in your insert statement, it is better to have some primary key in your table because you will find that deleting records or updating them may become impossible if you leave that out!