Form to delete data from MySQL database using PHP - php

Question

So I'm creating a small program with 2 forms, one to add data to a database, and one to delete from it. I've managed to create the first input form, but I'm slightly confused as to how I would get the second form to work. In the database "tasks" I have a table called "ID" which has the columns "ID", "Name" and "Hours"
Here's what the two HTML forms look like
<h2>Add Tasks</h2>
<form action="test.php" method="get">
Name of Task: <input type="text" name="name"><br />
Hours: <input type="number" name="hours"><br />
<input type="submit" value="Add" name="submit">
</form>
<h2>Delete Tasks</h2>
<form action="delete.php" method="get">
ID: <input type="number" name="ID"><br />
<input type="submit" value="Delete">
</form>
And the PHP for the first form "Add tasks" which inserts data
$servername = "localhost";
$username = "root";
$password = "root";
$conn = new mysqli($servername, $username, $password, "Tasks");
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
};
if (isset($_GET['submit'])) {
mysqli_select_db ($conn,"Tasks");
$name = $_GET['name'];
$hours = $_GET['hours'];
$sql = "INSERT INTO ID (Name, Hours) VALUES ('".$name."','". $hours."')";
$results = mysqli_query($conn,$sql);
$query = "SELECT `Name` FROM `ID`";
$result = mysqli_query($conn, $query);
$x=0;
And the PHP for the second form which deletes tasks. This is the part that is not working
if (isset($_GET['submit'])) {
mysqli_select_db ($conn, "Tasks");
$id = $_GET['id'];
$sql = "DELETE FROM ID (ID) VALUES ('".$id."')";
$query = "SELECT `Name` FROM `ID`";
$result = mysqli_query($conn, $query);
$x=0;
How should I format the PHP for the second button. I've basically reused the code for the first form. Do I need to differentiate it somehow from the first button? Currently the page is showing up completely blank. I'm a complete novice so any help would be appreciated.

Answer 1

Your SQL Statement
"DELETE FROM ID (ID) VALUES ('".$id."')"
is wrong.
It should be
DELETE FROM table_name
WHERE some_column=some_value;
. So, change your statement to
DELETE FROM ID WHERE ID='$id'
Suggestions
You should use POST method for action which will result in data edit.
You should check the input, make sure it did not contain SQL statement. A good way is to use $stuff = mysql_real_escape_string($_GET["stuff"]).

Answer 2

I see you have name 'ID' in the form but your are trying to get 'id'. That could be the problem

Answer 3

The sql statement for deletion should look something like the snippet below.
$sql = "DELETE FROM ID WHERE `id`=".$id.";";
$results = mysqli_query($conn,$sql);

Answer 4

In addition to above answers you should give different name to the both form input tags as
<h2>Add Tasks</h2>
<form action="test.php" method="get">
Name of Task: <input type="text" name="name"><br />
Hours: <input type="number" name="hours"><br />
<input type="submit" value="Add" name="submit">
</form>
<h2>Delete Tasks</h2>
<form action="delete.php" method="get">
ID: <input type="number" name="ID"><br />
<input type="submit" value="Delete" name="delete">
</form>
So for adding into database , you can use
if (isset($_GET['submit'])){
// your code here
}
And for deleting from database , you can use
if (isset($_GET['delete'])){
mysqli_select_db ($conn, "Tasks");
$id = $_GET['id'];
$sql = "DELETE FROM ID (ID) WHERE ID='".mysql_real_escape_string($id)."' ;
$query = "SELECT `Name` FROM `ID`";
$result = mysqli_query($conn, $query);
$x=0;
}
This will solve all the problems.
If you are using same name for the type="submit" in both forms than you can use POST method on one form and GET method on the other.
And yes mysql_real_escape_string is used to prevent SQL INJECTION.