What are the potential pitfalls of running a MySQL query within a loop in PHP?

Running a MySQL query within a loop in PHP can lead to performance issues due to the overhead of establishing a new database connection and executing the query multiple times. To solve this issue, it's recommended to fetch all the necessary data with a single query outside the loop and then iterate over the results in the loop. 

// Fetch all necessary data with a single query
$query = "SELECT * FROM table_name";
$result = mysqli_query($connection, $query);

// Check if the query was successful
if ($result) {
    // Iterate over the results in the loop
    while ($row = mysqli_fetch_assoc($result)) {
        // Process each row here
    }
} else {
    echo "Error: " . mysqli_error($connection);
}

// Free the result set
mysqli_free_result($result);

Keywords

MySQL query loop performance optimization database connection

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