SQL按行删除行

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.