What are common pitfalls when using JOIN queries in PHP to retrieve data from multiple tables?

Common pitfalls when using JOIN queries in PHP include not specifying the correct join type, not properly aliasing columns with the same name in multiple tables, and not handling NULL values correctly. To avoid these pitfalls, make sure to specify the correct join type (INNER JOIN, LEFT JOIN, RIGHT JOIN), alias columns with the same name, and handle NULL values appropriately. 

// Example of a JOIN query with proper join type, column aliasing, and handling NULL values
$query = "SELECT t1.id AS table1_id, t2.name AS table2_name 
          FROM table1 t1 
          INNER JOIN table2 t2 ON t1.id = t2.table1_id";

$result = mysqli_query($connection, $query);

if ($result) {
    while ($row = mysqli_fetch_assoc($result)) {
        $table1_id = $row['table1_id'];
        $table2_name = $row['table2_name'];
        // Process the retrieved data
    }
} else {
    echo "Error: " . mysqli_error($connection);
}

Keywords

JOIN queries PHP data retrieval multiple tables SQL errors

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