How to create a dynamic table column in database php

view js

    // **************************************************************

    // * Save data from input Field *

    // **************************************************************

    $(document).ready(function() {

        $('#submit').click(function(){

            // alert(23);

            $.ajax({

                // alert(23);

                    url:"<?php echo base_url('sell/AddInputFieldCurrency')?>",

                    method:"POST",

                    data:$('#add_name').serialize(),

                    type:'json',

                    success:function(data)

                    {

                        i=1;

                        $('.dynamic-added').remove();

                        $('#add_name')[0].reset();

                        //alert('Record Inserted Successfully.');                        

                    }

            });

        });

    });

controller

// ********************************************************

    // * AddInputFieldCurrency *

    // ********************************************************

    function AddInputFieldCurrency()

    {

        $currencyValue = $_POST['currencyValue'];

        $currencyName = $_POST['currencyName'];

        $data=array();

        $i=0;

        foreach($currencyValue as $key=>$value){

            $str = $value;

            $RemoveSpaceValue = str_replace(' ', '', $str); // space remove

            $data['currencyValue']=$RemoveSpaceValue;

            $data['currencyName']=$currencyName[$i];

            $data['date']=date('Y-m-d');

            $this->db->insert('currency',$data);

            $i++;

        }

        $exististable = $this->db->table_exists('paddycash');

        $servername = "localhost";

        $username = "root";

        $password = "";

        $dbname = "technodesk";

        // Create connection

        $conn = new mysqli($servername, $username, $password, $dbname);

        // Check connection

        if ($conn->connect_error)

        {

            die("Connection failed: " . $conn->connect_error);

        }

        if(!empty($exististable))

        {

            foreach($currencyName as $value)

            {

                $str = $value;

                $RemoveSpaceValue = str_replace(' ', '', $str); // space remove

                $sql = "ALTER TABLE paddycash ADD {$RemoveSpaceValue} VARCHAR(255)
NULL";   

                $conn->query($sql);

            }

        }

    }