What are the potential pitfalls of not combining queries in PHP when fetching data from multiple tables?

Not combining queries in PHP when fetching data from multiple tables can result in multiple round trips to the database, leading to slower performance and potential data inconsistency if the tables are being updated concurrently. To solve this issue, you can use JOIN statements in your SQL query to fetch data from multiple tables in a single query, reducing the number of database calls and ensuring data integrity. 

<?php
// Connect to the database
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');

// Fetch data from multiple tables using JOIN
$query = "SELECT t1.column1, t2.column2
          FROM table1 t1
          JOIN table2 t2 ON t1.id = t2.table1_id
          WHERE t1.some_condition = :condition";

$stmt = $pdo->prepare($query);
$stmt->execute(['condition' => 'some_value']);

// Fetch the results
$results = $stmt->fetchAll(PDO::FETCH_ASSOC);

// Process the results
foreach ($results as $result) {
    // Do something with the data
}
?>

Keywords

SQL injection performance data consistency code readability JOIN queries

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