PHP MySQLi mysqli_use_result() - Direct Reading of Results

mysqli_use_result()

The mysqli_use_result() function initiates the retrieval of a result set from the last query. Unlike store_result(), this function does not transfer all data into local memory but reads it row by row directly from the server.

EXAMPLE

<?php
$server = "localhost";
$username = "root";
$password = "";
$database = "mysqli_database";

$connection = mysqli_connect($server, $username, $password, $database);

if (mysqli_connect_errno()) {
    echo "Connection failed: " . mysqli_connect_error();
    exit();
}

// Prepare two separate SELECT queries, separated by a semicolon
$sql = "SELECT fruit FROM mysqli_table; SELECT vegetable FROM mysqli_table";

// Execute multiple queries simultaneously using the mysqli_multi_query function
if (mysqli_multi_query($connection, $sql)) {
    do {
        // NOTE: mysqli_use_result() DOES NOT store the entire result in PHP RAM, 
        // but instead allows real-time reading of rows directly from the server (one by one). When working 
        // with mysqli_multi_query, this function is essential because we must completely "flush" (read in a loop) 
        // the current result set before the database allows us to proceed to the next SELECT command.
        if ($result = mysqli_use_result($connection)) {
            while ($row = mysqli_fetch_row($result)) {
                printf("%s<br>", $row[0]);
            }
            // As soon as we finish the loop, free the current result
            mysqli_free_result($result);
        }
        
        // If there is another SELECT command waiting in line, print a separator line
        if (mysqli_more_results($connection)) {
            printf("------------<br>");
        }
        
        // Move to the next result set (the next SELECT)
    } while (mysqli_next_result($connection));
}

mysqli_close($connection);
?>

RESULT

The result will be displayed here...

Practical use: This is ideal for working with extremely large databases, where transferring all data at once would consume too much RAM. It is often used in combination with mysqli_multi_query() when processing multiple SQL commands sequentially.

Minimal PHP memory (RAM) consumption, as rows are read on the fly.

It starts returning the first rows very quickly because it does not wait for the complete transfer.

Important: During retrieval, the server connection is busy, and you cannot execute new queries.