Get the number of rows affected by multiple delete - php

Question

How can I get a count of the number of affected rows when I'm deleting multiple rows in PDO? This is the technique I'm using to delete multiple rows:
$selected = $_POST['checkbox'];
$N = count($selected);
for ($i = 0; $i < $N; $i++) {
$result = $dbh->prepare('DELETE FROM users WHERE id= :id');
$result->bindParam(':id', $selected[$i], PDO::PARAM_INT);
$result->execute();
}
I tried this, but it always returned 1:
$deleted = $result->rowCount();
if ($deleted) {
echo $deleted.' was deleted.';
}

Answer 1

You're running a loop, so each call is deleting 1; you need to add a counter.
So add:
$deleted += $result->rowCount();
inside the loop
and then outside:
if ($deleted) {
echo $deleted.' was deleted.';
}

Answer 2

If the id field is unique, then that statement could affect at most 1 row. However you are preparing a new statement and executing it in a loop. You should try adding up how many you delete.
$deleted = 0;
for ($i = 0; $i < $N; $i++) {
$result = $dbh->prepare('DELETE FROM users WHERE id= :id');
$result->bindParam(':id', $selected[$i], PDO::PARAM_INT);
$result->execute();
$deleted = $deleted + $result->rowCount();
}
echo $deleted.' was deleted.';

Answer 3

Here's a way to do it in 1 delete instead of running multiple deletes.
This way rowCount() will show the actual results deleted.
$selected = $_POST['checkbox'];
$placeholder = array();
$values = array();
foreach ($selected as $id) {
$placeholder[] = ":".$id;
$values[":".$id] = $id;
}
$sql = "Delete FROM users WHERE id IN (".implode(', ',$placeholder).") ";
$result = $dbh->prepare($sql);
$result->execute($values);
$deleted = $result->rowCount();
if ($deleted>0) {
echo $deleted.' was deleted.';
}