Fetch-Next-Index-in-table-in-MySQL-

fetch next index in MySQL table

All Error Headling of this code
-- can not enter entered id in the table
-- only can enter next id according to the following table in project

university project

Code :
function/functions.php

<?php 
    use FTP\Connection; 
    include_once("config.php");

    function add_user($id, $email, $usr_name){
        $con = Connection();
        $get_next_id = strval($_SESSION['nextId']);

        $check_sql = "SELECT * FROM user_tbl WHERE id = '$id' || email = '$email'";
        $check_sql_result = mysqli_query($con, $check_sql);

        $check_sql_nor = mysqli_num_rows($check_sql_result);

        if($check_sql_nor > 0){
            return "<center>&nbsp<div class='alert alert-danger col-10' role='alert'>User Already Exists..!</div>&nbsp</center>";
        }else{
            if($id == $get_next_id){
                $insert_user = "INSERT INTO user_tbl(id,email,usr_name)VALUES('$id','$email','$usr_name')";
                $insert_user_result = mysqli_query($con, $insert_user);
                header("location:index.php");
            }
            else{
                return "<center>&nbsp<div class='alert alert-danger col-10' role='alert'>Your entered id is ".$id."...! Enter ".$get_next_id." as Index                                   Number</div>&nbsp</center>";
            }

        }        
    }

    function all_user(){
        $con = Connection();

        $all_users = "SELECT * FROM user_tbl";
        $all_user_result = mysqli_query($con, $all_users);

        while($user_row = mysqli_fetch_assoc($all_user_result)){
            echo"<tr>
                    <td>".$user_row['id']."</td>
                    <td>".$user_row['email']."</td>
                    <td>".$user_row['usr_name']."</td>
                </tr>";
        }
    }


    function next_id(){
        $con = Connection();

        $get_last_index = "SELECT id FROM user_tbl ORDER BY id DESC LIMIT 1";
        $get_last_index_result = mysqli_query($con, $get_last_index);

        $last_index = mysqli_fetch_assoc($get_last_index_result);

        $next_index = $last_index['id'] + 1;
        echo $next_index;
        $_SESSION['nextId'] = $next_index;      
    }
?>

Fetch Next Index....

function next_id(){
    $con = Connection();

    $get_last_index = "SELECT id FROM user_tbl ORDER BY id DESC LIMIT 1";
    $get_last_index_result = mysqli_query($con, $get_last_index);

    $last_index = mysqli_fetch_assoc($get_last_index_result);

    $next_index = $last_index['id'] + 1;
    echo $next_index;
    $_SESSION['nextId'] = $next_index;      
}

According to above part of code,
I fetch the last index using following lines

    $get_last_index = "SELECT id FROM user_tbl ORDER BY id DESC LIMIT 1";
    $get_last_index_result = mysqli_query($con, $get_last_index);

    $last_index = mysqli_fetch_assoc($get_last_index_result);

and then I want to get next index, so that
I add 1 for the last index like following

    $next_index = $last_index['id'] + 1;
    echo $next_index;

and last line is optical,

    $_SESSION['nextId'] = $next_index;

This is Optical

because I want to check user input id is equal to last index+1 in table the next id, so then I get that last id and
check it in

user_add() function

function add_user($id, $email, $usr_name){
    $con = Connection();
    $get_next_id = strval($_SESSION['nextId']);

    $check_sql = "SELECT * FROM user_tbl WHERE id = '$id' || email = '$email'";
    $check_sql_result = mysqli_query($con, $check_sql);

    $check_sql_nor = mysqli_num_rows($check_sql_result);

    if($check_sql_nor > 0){
        return "<center>&nbsp<div class='alert alert-danger col-10' role='alert'>User Already Exists..!</div>&nbsp</center>";
    }else{
        if($id == $get_next_id){
            $insert_user = "INSERT INTO user_tbl(id,email,usr_name)VALUES('$id','$email','$usr_name')";
            $insert_user_result = mysqli_query($con, $insert_user);
            header("location:index.php");
        }
        else{
            return "<center>&nbsp<div class='alert alert-danger col-10' role='alert'>Your entered id is ".$id."...! Enter ".$get_next_id." as Index                                   Number</div>&nbsp</center>";
        }

    }        
}

converting Session to String like following

$get_next_id = strval($_SESSION['nextId']);

then check it,

        if($id == $get_next_id){
            $insert_user = "INSERT INTO user_tbl(id,email,usr_name)VALUES('$id','$email','$usr_name')";
            $insert_user_result = mysqli_query($con, $insert_user);
            header("location:index.php");
        }
        else{
            return "<center>&nbsp<div class='alert alert-danger col-10' role='alert'>Your entered id is ".$id."...! Enter ".$get_next_id." as Index                                   Number</div>&nbsp</center>";
        }

in here $id is user input id
and $get_next_id is the next id according to the table

DEVELOPER : JEHANKANDY
THANK YOU

JehanKandy/Fetch-Next-Index-in-table-in-MySQL-

Fetch-Next-Index-in-table-in-MySQL-