MySQL SELECT with multiple conditions - php

Question

When searching for available cars, I'm trying to SELECT from cars table WHERE the IDs do not include the already booked cars.
For that, I used :
$result = $pdo->prepare("SELECT * FROM cars
WHERE id NOT IN (" . implode(',', $bookedCarIds) . ")
AND (location = '$fromlocation' AND fromdate BETWEEN '$fromdate' AND '$todate')
");
$result->execute();
$availableCars = [];
$availableCars = $result->fetchAll();
Which works perfectly fine.
However, the issue arises when there are no already booked cars in the selected location and dates (where $bookedCarsIds is NULL). To deal with this issue, I used the following code, which throws a syntax error.
$result = $pdo->prepare("SELECT * FROM cars
WHERE id NOT IN (" . implode(',', $bookedCarIds) . ") AND
(location = '$fromlocation' AND fromdate BETWEEN '$fromdate' AND '$todate')
OR WHERE location = '$fromlocation' AND fromdate BETWEEN '$fromdate' AND '$todate'
");
$result->execute();
$availableCars = [];
$availableCars = $result->fetchAll();
How can I solve this issue by making changes in this MySQL query alone, without altering the rest of my code?
Thank you.

Answer 1

If you are using PDO, you need to create a dynamic WHERE clause with parameters like in this example:
$whereClause = [];
$params = [];
if (!empty($bookedCarIds)) {
$whereClause[] = 'id NOT IN (?' . str_repeat(', ?', count($bookedCarIds) - 1) . ')';
$params = $bookedCarIds;
}
if (!empty($fromlocation)) {
$whereClause[] = 'location = ?';
$params[] = $fromlocation;
}
if (!empty($fromdate) && !empty($todate)) {
$whereClause[] = 'fromdate BETWEEN ? AND ?';
$params[] = $fromdate;
$params[] = $todate;
}
$whereClause = !empty($whereClause) ? 'WHERE ' . implode(' AND ', $whereClause) : '';
$result = $pdo->prepare("SELECT * FROM cars $whereClause");
$result->execute($params);
$availableCars = $result->fetchAll();