SQL Delete Row by id - php

Question

I'm trying to delete a row in an SQL database by an id. I have found questions here related to this but nothing seems to work, perhaps because my page is populated (dynamically?) based on selecting a variable. The rows are displayed on my page based on a dropdown (locationlab) and I have a delete button after each row. It looks like this.
I have the Id displayed temporarily at the end of the row just be sure that the code sees the variable (& it does!).
The code to populate the page looks like this:
<?php
$locationlab = $_POST[locationlab];
$sql = "SELECT * FROM lab WHERE locationlab LIKE '{$locationlab}'";
echo($locationlab);
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo'
<table>
<form action=testpage2.php method=post>
<td width="10%"><input type=text name=make value='. $row["make"].'></td>
<td width="10%"><input type=text name=model value='. $row["model"].'></td>
<td width="20%"><input type=text name=hostname value='. $row["hostname"].'></td>
<td width="15%"><input type=text name=ipaddress value='. $row["ipaddress"].'></td>
<td width="20%"><input type=text name=ipmiipaddress value='. $row["ipmiipaddress"].'></td>
<td width="15%"><input type=text name=terminalserveraddress value='. $row["terminalserveraddress"].'></td>
<td width="10%"><input type=text name=locationlab value='. $row["locationlab"].'></td>
<td><input type=submit name=update value=update></td>
<td><input type=submit name=delete value=delete></td>
<td id=id name=id value='. $row["id"].'>'. $row["id"].'</td>
</table>
</form>';
}}
?>
I can input the SQL query below manually in the phpMyAdmin page so I know it is correct.
The code for the Delete button looks like this:
<?php
if(isset($_POST['delete'])) {
$deletequery = ("DELETE * FROM lab WHERE ='$_POST[id]'");
mysql_query($deletequery, $conn);
};
?>
When I click the delete button it appears to refresh the page but nothing changes. I imagine that if I can get the delete button working, the update will work in a similar fashion but for now I'm stumped.

Answer 1

<?php
if(isset($_POST['delete'])) {
$deletequery = ("DELETE FROM lab WHERE **columnName** ='$_POST[id]'");
mysql_query($deletequery, $conn);
}
?>
You are missing column name in query. Also there is no * in DELETE statement, because deleting means deleting row.

Answer 2

First of all let me help you in formatting the code
you should not write entire HTML code in echo...
instead try this one....
<?php
while($row = $result->fetch_assoc()) {
?>
<table>
<form action="testpage2.php" method="pos">
<td width="10%"><input type="text" name="make" value="<?= $row["make"] ?>"></td>
....
....
</table>
</form>
<?php
}
?>
also you should use mysqli instead of mysql
and your database query is also incorrect, it must be like this..
DELETE FROM lab WHERE id ='$_POST[id]'
if you use mysqli then you can also use some functions like this..
mysqli_query($con,$deletequery)
if(mysqli_errno($con))
{
echo("SOme error while executing query : ".mysqli_error($con));
}