Last updated: Fri, 20 Nov 2009

mysqli_stmt->affected_rows

mysqli_stmt_affected_rows

(PHP 5)

mysqli_stmt->affected_rows -- mysqli_stmt_affected_rows — Returns the total number of rows changed, deleted, or inserted by the last executed statement

Description

Object oriented style (property):

mysqli_stmt

int $affected_rows;

Procedural style :

int mysqli_stmt_affected_rows ( mysqli_stmt $stmt )

Returns the number of rows affected by INSERT, UPDATE, or DELETE query.

This function only works with queries which update a table. In order to get the number of rows from a SELECT query, use mysqli_stmt_num_rows() instead.

Parameters

stmt: Procedural style only: A statement identifier returned by mysqli_stmt_init().

Return Values

An integer greater than zero indicates the number of rows affected or retrieved. Zero indicates that no records where updated for an UPDATE/DELETE statement, no rows matched the WHERE clause in the query or that no query has yet been executed. -1 indicates that the query has returned an error. NULL indicates an invalid argument was supplied to the function.

Note: If the number of affected rows is greater than maximal PHP int value, the number of affected rows will be returned as a string value.

Examples

Example #1 Object oriented style


<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* create temp table */
$mysqli->query("CREATE TEMPORARY TABLE myCountry LIKE Country");

$query = "INSERT INTO myCountry SELECT * FROM Country WHERE Code LIKE ?";

/* prepare statement */
if ($stmt = $mysqli->prepare($query)) {

    /* Bind variable for placeholder */
    $code = 'A%';
    $stmt->bind_param("s", $code);

    /* execute statement */
    $stmt->execute();

    printf("rows inserted: %d\n", $stmt->affected_rows);

    /* close statement */
    $stmt->close();
}

/* close connection */
$mysqli->close();
?>

Example #2 Procedural style


<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* create temp table */
mysqli_query($link, "CREATE TEMPORARY TABLE myCountry LIKE Country");

$query = "INSERT INTO myCountry SELECT * FROM Country WHERE Code LIKE ?";

/* prepare statement */
if ($stmt = mysqli_prepare($link, $query)) {

    /* Bind variable for placeholder */
    $code = 'A%';
    mysqli_stmt_bind_param($stmt, "s", $code);

    /* execute statement */
    mysqli_stmt_execute($stmt);

    printf("rows inserted: %d\n", mysqli_stmt_affected_rows($stmt));

    /* close statement */
    mysqli_stmt_close($stmt);
}

/* close connection */
mysqli_close($link);
?>

The above example will output:

rows inserted: 17


This property contains a -1 value in situations when no errors have occurred.  When preparing a SELECT statement (or any other statement which doesn't affect rows), the property will be -1.  The property will also be reset to -1 if an INSERT statement is re-prepared as a SELECT statement.



For example:

<?php

    $mysqli = new mysqli('localhost', 'user', 'pass', 'test');

    $stmt = $mysqli->stmt_init();

    $param = 'value';



    //First SELECT

    $stmt->prepare('SELECT * FROM `test` WHERE `field`=?');

    $stmt->bind_param('s', $param);

    var_dump($stmt->execute());

    var_dump($stmt->affected_rows);

    echo '<br>';



    //INSERT

    $stmt->prepare('INSERT INTO `test` (`field`) VALUES (?)');

    $stmt->bind_param('s', $param);

    var_dump($stmt->execute());

    var_dump($stmt->affected_rows);

    echo '<br>';



    //Second SELECT

    $stmt->prepare('SELECT * FROM `test` WHERE `field`=?');

    $stmt->bind_param('s', $param);

    var_dump($stmt->execute());

    var_dump($stmt->affected_rows);

    echo '<br>';

?>



Displays:

bool(true) int(-1)

bool(true) int(1)

bool(true) int(-1)

Chuck
29-Apr-2007 05:51


I'm not sure whether or not this is the intended behavior, but I noticed through testing that if you were to use transactions and prepared statements together and you added a single record to a database using a prepared statement, but later rolled it back, mysqli_stmt_affected_rows will still return 1.

Carl Olsen
27-Dec-2005 06:34


It appears that an UPDATE prepared statement which contains the same data as that already in the database returns 0 for affected_rows.  I was expecting it to return 1, but it must be comparing the input values with the existing values and determining that no UPDATE has occurred.

add a note

mysqli_stmt::attr_get

MySQLi_STMT