How to delete mysql database data from table, using php - php

Question

I have a problem with my PHP code, I can't get it to delete some data inside my MySQL database. I have tried some different things but it just won't work.
What iv'e tried: Deleting $productId, switched $producId to 1, 2, 3 and 4.
if (isset($_POST['remove_product'])) {
$productId = 4
$sql = "DELETE FROM products WHERE id = '.$productId.'";
$stmt = mysqli_init($conn);
if (!mysqli_prepare($stmt, $sql)) {
header("Location: products.php?error=sqlerror");
exit();
} else {
mysqli_execute($stmt);
}
}
I would like if it could delete the data from the MySQL table, so if someone could come with a solution, thanks : )
Thanks!

Answer 1

You are using the wrong functions to initialise, prepare and execute your statement. You should be using mysqli_stmt_init, mysqli_stmt_prepare and mysqli_stmt_execute instead. Also, since you are preparing a statement, you should take advantage of that to avoid SQL injection. Try this:
if (isset($_POST['remove_product'])) {
$productId = 4;
$sql = "DELETE FROM products WHERE id = ?";
$stmt = mysqli_stmt_init($conn);
if (!mysqli_stmt_prepare($stmt, $sql)) {
header("Location: products.php?error=sqlerror");
exit();
}
else {
mysqli_stmt_bind_param($stmt, 'i', $productId);
mysqli_stmt_execute($stmt);
}
}

Answer 2

You are lacking a semicolon
$productId = 4
--------------^
Use
$productId = 4;
You have some issues with quotation marks:
$sql = "DELETE FROM products WHERE id = '.$productId.'";
-------^--------------------------------^------------^^
It should say:
$sql = "DELETE FROM products WHERE id = " . $productId;
Also you are not using prepared statements in the right way
if (isset($_POST['remove_product'])) {
$productId = 4;
$sql = "DELETE FROM products WHERE id = ?";
if (!$stmt = mysqli_prepare($sql)) {
header("Location: products.php?error=sqlerror");
exit();
} else {
$stmt->bind_params("i", $productId);
$stmt->execute();
}
}

Answer 3

There are some syntactic mistakes in your code. Use mysqli-query to execute the the query. it is used frequently
if (isset($_POST['remove_product'])) {
$productId = 4;
$sql = "DELETE FROM products WHERE id = ".$productId;
$stmt = mysqli_init($conn);
if (!mysqli_query($stmt, $sql)) {
header("Location: products.php?error=sqlerror");
exit();
} else {
mysqli_execute($stmt);
}
}
try this once