What are some potential pitfalls when querying linked tables in PHP?

When querying linked tables in PHP, a common pitfall is not properly joining the tables in the SQL query. This can result in incorrect or incomplete results being returned. To avoid this issue, make sure to use the appropriate JOIN clause to link the tables together based on their relationships. 

// Example of querying linked tables with a proper JOIN clause
$query = "SELECT t1.column1, t2.column2 
          FROM table1 t1 
          JOIN table2 t2 ON t1.id = t2.table1_id 
          WHERE t1.some_condition = 'value'";

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

if ($result) {
    // Process the query result
} else {
    echo "Error: " . mysqli_error($connection);
}

Keywords

SQL injection JOIN statements foreign keys PDO database normalization

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