Insert Query not working in the form

Many people has asked the same question, I have read those things and mine is different,

I am trying to insert some values inside the database from the form but it’s not getting inserted

I have a table in the database having 6 columns wanted to insert some values inside only of 4 columns

**Table Name: wp_contactus**

6 Columns
——-

– id
– firstname
– lastname
– email
– query
– reg_date

This is the code for inserting only in the 4 columns

4 Columns
———

– firstname
– secondname
– email
– query

<?php
function contactus_shortcode(){ ?>

<div class=”wrap”>
<form action=”” method=”post”>
FirstName <input type=”text” name=”firstNametxt” value=”” />
LastName <input type=”text” name=”lastNametxt” value=”” />
email <input type=”text” name=”email” value=”” />
Query <input type=”text” name=”query” value=”” />
<input name=”Submit” type=”submit” value=”Submit”>
</form>
<form method=”post”>
<?php
global $wpdb;
$firstName = $_POST[“firstNametxt”];
$lastName = $_POST[“lastNametxt”];
$email = $_POST[“email”];
$query = $_POST[“query”];

echo $firstName;
$contactus_table = $wpdb->prefix.”contactus”;

$sql = “INSERT INTO $contactus_table (id, firstname, lastname, email,

query, reg_date) VALUES (‘2’, $firstName, $lastName, $email, $query,

CURRENT_TIMESTAMP);”;

$wpdb->query($sql))

?>
</form>
</div>

<?php
}
add_shortcode( ‘CONUS’, ‘contactus_shortcode’ );

?>