Data failing to insert into mysql


#1
		<div class="col-sm-6 col-md-6 col-md-offset-3" style="margin-top: 50px;">
		  <form action="signup.php" method="POST" enctype="multipart/form-data">
			<label>First Name: </label>
			<input type="text" name="first_name" placeholder="First Name" class="form-control"><br>
			<label>Second Name: </label>
			<input type="text" name="secname" placeholder="Second Name" class="form-control"><br>
			<label>Surname: </label>
			<input type="text" name="surname" placeholder="Surname" class="form-control"><br>
			<label>Email: </label>
			<input type="email" name="email" placeholder="Enter your email here" class="form-control"><br>
			<label>Phone Number</label>
			<input type="text" name="phone" placeholder="phone Number" class="form-control"><br>
			<label>Date of Birth</label>
			<input type="date" name="dob" placeholder="Date of Birth" class="form-control"><br>
			<label>Password</label>
			<input type="password" name="pass1" placeholder="Password" class="form-control"><br>
			<label>Confirm Password</label>
			<input type="password" name="pass2" placeholder="Confirm Password" class="form-control"><br>
			<input type="submit" name="Submit" value="Signup" class="btn btn-primary">
			<h5>Have an account? <a href="login.php">Login</a></h5>
			
		  </form>
				<?php 
				if (isset($_POST['submit'])) {
					$first_name = $POST['first_name'];
				 	$secname = $POST['secname'];
				 	$surname = $POST['surname'];
				 	$email = $POST['email'];
				 	$phone = $POST['phone'];
				 	$dob = $POST['dob'];
				 	$pass1 = $POST['pass1'];
				 	$pass2 = $POST['pass2'];


				 	$sql_insert ="INSERT INTO admin (id,first,sec,sur,email,phone,dob,pass1,pass2) VALUES(NULL'$first_name', '$secname', '$surname', '$email', '$phone', '$dob', '$pass1', '$pass2')";
				 	mysqli_query($conn, $sql_insert);

				 	header("location: signup.php?signup=success");	
				}else{
					 		echo '<div class="alert alert-danger">';
	                        echo "There was an error in inserting data!";
	                        echo '</div';

				}

				 	
				

				  ?>
			
		</div>

#2

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