In PHP, what are the advantages of using a subquery to filter results based on multiple criteria compared to using a single query with multiple WHERE clauses?

Using a subquery to filter results based on multiple criteria in PHP can be advantageous because it allows for more complex filtering logic to be applied in a structured and organized manner. This approach can also improve code readability and maintainability by breaking down the filtering criteria into separate logical units. Additionally, using subqueries can often result in better performance compared to using multiple WHERE clauses in a single query, especially when dealing with large datasets. 

<?php
// Using a subquery to filter results based on multiple criteria
$query = "SELECT * FROM table_name WHERE id IN (SELECT id FROM other_table WHERE condition1 = 'value1' AND condition2 = 'value2')";
$result = mysqli_query($connection, $query);

// Process the results
if (mysqli_num_rows($result) > 0) {
    while ($row = mysqli_fetch_assoc($result)) {
        // Handle each row of data
    }
} else {
    echo "No results found.";
}
?>

Keywords

PHP subquery filter multiple criteria WHERE clause

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