PHP MySQLi mysqli_data_seek() - Moving the Pointer

mysqli_data_seek()

The mysqli_data_seek() function adjusts the result pointer to an arbitrary row in the result set. What is a pointer? Imagine that the data in the database are like lines in a book. When we execute a query, PHP "takes note of the page" where it left off. Each time we call a read function (fetch), PHP reads the row, and the invisible bookmark (pointer) moves to the next row. When we reach the end, the pointer has nothing left to show and returns an empty value.

EXAMPLE

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

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

$query = "SELECT fruit, vegetable FROM mysqli_table ORDER BY table_id";

if ($result = mysqli_query($connection, $query)) {
    // NOTE: Row indices always start at 0 (0 is the 1st row, 1 is the 2nd row...).
    // Since we want to jump directly to the 3rd row in the table (Orange), 
    // we tell the database to move the pointer to index 2, thereby skipping the first two rows.
    mysqli_data_seek($result, 2);
    $row = mysqli_fetch_row($result);
    
    echo "Fruit: " . $row[0] . "<br>";
    echo "Vegetable: " . $row[1];
    
    mysqli_free_result($result);
}

mysqli_close($connection);
?>

RESULT

The result will be displayed here...

Practical use: We use this function when we do not want to read rows in sequential order, but instead want to jump directly to a specific record (e.g., to the fifth row). Test it at home like this:

Row counting starts with 0 (0 is the first row, 1 is the second...).

The function returns true on success and false on failure.

It is useful if you want to read the same result set multiple times from different positions.