MySQL SELECT with multiple conditions

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.

user_14717238 · Answer

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();

MySQL SELECT with multiple conditions

1 Answers