Search Engine Script - Undefined variables - php

Question

I have a small problem in my code and I can't figure out what is it..
I'm trying to make a sample search engine tool in PHP , everything works good until i've tryied to search some posts from database... When I do that , it says I don't have $header and $bio declared ...
<?php
include('connection.php');
$query =mysqli_real_escape_string($dbc, $_POST['query']);
$q = mysqli_query($dbc, "SELECT id FROM search WHERE header LIKE '%$query%' OR bio LIKE '%$query%'");
$num = mysqli_num_rows($q);
echo $num;
if(!$query){
echo "Enter a query...";
} else {
if($num != 0)
{
echo "<hr>";
while ($fetch = mysqli_fetch_assoc($q)){
$id = $fetch['id'];
$header = $fetch['header'];
$bio = $fetch['bio'];
echo "<strong>" . $header . "</strong>";
echo "<blockquote><p>" . $bio . "</p></blockquote>";
echo "<hr>";
}
} else {
echo "No results where found .. ";
}
}
?>
and the form
<div style = "width:300px; margin:auto;">
<h1> Add Search Criteria</h1>
<p> Type a header and bio below to add to search engine</p>
<p>
<input id="header" name = "header" type="text" placeholder="header" style="width:100%;">
</p>
<p>
<textarea id="bio" name="bio" cols="40" rows="7" placeholder="Write a bio.."></textarea>
</p>
<p>
<center>
<button id="submit">Submit Search</button>
</center>
</p>
<div id="add_error" style="text-align:center"></div>
<hr>
<h1>Search The Database</h1>
<p>Please type something to search to database</p>
<p>
<input name = "query" id="query" type="text" placeholder="search">
<button id="search">Search</button>
</p>
<div id="search_error">
</div>
</div>
this is what it outputs
Notice: Undefined index: header in C:\wamp64\www\mywebsite\Search\search.php on line 25
Call Stack
Time Memory Function Location
1 0.0021 242472 {main}( ) ...\search.php:0
( ! ) Notice: Undefined index: bio in C:\wamp64\www\mywebsite\Search\search.php on line 26
Call Stack
Time Memory Function Location
1 0.0021 242472 {main}( ) ...\search.php:0

Answer 1

Add header and bio columns in your select query.
$q = mysqli_query($dbc, "SELECT id, header, bio FROM search WHERE header LIKE '%$query%' OR bio LIKE '%$query%'");