What are the advantages of using INNER JOIN in SQL queries when retrieving hierarchical data for display in PHP?

When retrieving hierarchical data for display in PHP, using INNER JOIN in SQL queries can help efficiently retrieve related data from multiple tables in a single query. This can reduce the number of queries needed to fetch the necessary data and improve performance. Additionally, INNER JOIN ensures that only matching records are returned, which can help maintain data integrity in the hierarchical structure. 

// Example SQL query using INNER JOIN to retrieve hierarchical data
$query = "SELECT employees.name, departments.department_name
          FROM employees
          INNER JOIN departments ON employees.department_id = departments.id";
$result = mysqli_query($connection, $query);

// Display the retrieved data
while ($row = mysqli_fetch_assoc($result)) {
    echo "Employee: " . $row['name'] . " | Department: " . $row['department_name'] . "<br>";
}

Keywords

INNER JOIN SQL queries hierarchical data display PHP

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