MySQLi
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mysqli::$affected_rows

mysqli_affected_rows

(PHP 5)

mysqli::$affected_rows -- mysqli_affected_rows — Gets the number of affected rows in a previous MySQL operation

说明

面向对象风格

int $mysqli->affected_rows;

过程化风格

int mysqli_affected_rows ( mysqli $link )

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

For SELECT statements mysqli_affected_rows() works like mysqli_num_rows().

参数

link

仅以过程化样式：由 mysqli_connect() 或 mysqli_init() 返回的链接标识。

返回值

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

Note:

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

范例

Example #1 $mysqli->affected_rows example

面向对象风格

<?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();
}

/* Insert rows */
$mysqli->query("CREATE TABLE Language SELECT * from CountryLanguage");
printf("Affected rows (INSERT): %d\n", $mysqli->affected_rows);

$mysqli->query("ALTER TABLE Language ADD Status int default 0");

/* update rows */
$mysqli->query("UPDATE Language SET Status=1 WHERE Percentage > 50");
printf("Affected rows (UPDATE): %d\n", $mysqli->affected_rows);

/* delete rows */
$mysqli->query("DELETE FROM Language WHERE Percentage < 50");
printf("Affected rows (DELETE): %d\n", $mysqli->affected_rows);

/* select all rows */
$result = $mysqli->query("SELECT CountryCode FROM Language");
printf("Affected rows (SELECT): %d\n", $mysqli->affected_rows);

$result->close();

/* Delete table Language */
$mysqli->query("DROP TABLE Language");

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

过程化风格

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

if (!$link) {
    printf("Can't connect to localhost. Error: %s\n", mysqli_connect_error());
    exit();
}

/* Insert rows */
mysqli_query($link, "CREATE TABLE Language SELECT * from CountryLanguage");
printf("Affected rows (INSERT): %d\n", mysqli_affected_rows($link));

mysqli_query($link, "ALTER TABLE Language ADD Status int default 0");

/* update rows */
mysqli_query($link, "UPDATE Language SET Status=1 WHERE Percentage > 50");
printf("Affected rows (UPDATE): %d\n", mysqli_affected_rows($link));

/* delete rows */
mysqli_query($link, "DELETE FROM Language WHERE Percentage < 50");
printf("Affected rows (DELETE): %d\n", mysqli_affected_rows($link));

/* select all rows */
$result = mysqli_query($link, "SELECT CountryCode FROM Language");
printf("Affected rows (SELECT): %d\n", mysqli_affected_rows($link));

mysqli_free_result($result);

/* Delete table Language */
mysqli_query($link, "DROP TABLE Language");

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

以上例程会输出：

Affected rows (INSERT): 984
Affected rows (UPDATE): 168
Affected rows (DELETE): 815
Affected rows (SELECT): 169

参见

MySQLi
在线手册：中文 英文
PHP手册
PHP手册 - N: Gets the number of affected rows in a previous MySQL operation

用户评论:

ric at xpellshop dot com (10-Jul-2011 07:54)

"Zero indicates that no records where updated for an UPDATE statement, no rows matched the WHERE clause in the query or that no query has yet been executed."

what if i need to know which one of the three occurred? It's dumb that there is no distinction between the three.

Anonymous (18-Feb-2011 10:50)

On "INSERT INTO ON DUPLICATE KEY UPDATE" queries, though one may expect affected_rows to return only 0 or 1 per row on successful queries, it may in fact return 2.

From Mysql manual: "With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if the row is inserted as a new row and 2 if an existing row is updated."

See: http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

Here's the sum breakdown _per row_:
+0: a row wasn't updated or inserted (likely because the row already existed, but no field values were actually changed during the UPDATE)
+1: a row was inserted
+2: a row was updated

djnigelharkness at yahoo dot com (12-May-2010 01:42)

<?php
    $gHostName    ="localhost";   
    $gUserName    ="root";
    $gPassword    ="mypassword";
    $gDBName     ="dbName";
    $mysqli = new mysqli($gHostName, $gUserName, $gPassword,    
            $gDBName);
   
    $username="username";    $email="user@xxx.edu";
    $password="3442f6e94a733237a3e844f0286b92f559bf794d";
   
    //insert
//    $stmt = $mysqli->prepare("INSERT INTO j_user
        (username,email,password) VALUES (?, ?, ?)");
//    $stmt->bind_param('sss',$username, $email, $password);
//    $stmt->execute();
//    $stmt->close();

    //delete
//    $stmt = $mysqli->prepare("DELETE FROM j_user WHERE
                        username=?");
//    $stmt->bind_param('s',$username);
//    $stmt->execute();
//    $stmt->close();

    //update
//    $stmt = $mysqli->prepare("UPDATE j_user SET email=? WHERE
                        username='wjw6349'");
//    $stmt->bind_param('s',$email);
//    $stmt->execute();
//    $stmt->close();

    if ($mysqli->connect_error){
        echo("Connect failed: ".mysqli_connect_error()); exit();
    }

    $querySelect = "SELECT * FROM j_user";
    $resultSet = $mysqli->query($querySelect);
   
    if($resultSet->num_rows > 0){
        while($row = $resultSet->fetch_assoc()){
            foreach($row as $fieldValue){
                $bigString .= "<em>$fieldValue</em><br />\n";
            }
            $bigString .= "<hr />";
        }
        $mysqli->close();
        echo $bigString;
    }

    function __autoload($className) {
        require_once $className.'.class.php';
    }
    //start the session and create it
    session_start();
    $_SESSION['name'] = $_POST['username']."_".time();
    //encrypt the password   
    sha1($_POST['password']) == $password
    header("Location:admin.php");
    //check if the session is set
    session_start();
    if (isset($_SESSION['name'])) { }
?>

oilpc at oilpc dot com (14-Nov-2009 06:06)

For "INSERT" or "UPDATE" statement for modifying data contained in one row of one table I checked if number of affected rows equals 1 to determine success of the operation. It works fine both for errors and false value of WHERE condition (that might be generated according to specific application user acces privileges).
<?php
if ($mysqli->affected_rows==1){
    echo "success";
}
else {
    echo "fail";
}
?>

Checking if mysqli->affected_rows will equal -1 or not is not a good method of determining success of "INSERT IGNORE" statements. Example: Ignoring duplicate key errors while inserting some rows containing data provided by user only if they will match specified unique constraint causes returning of -1 value by mysqli->affected_rows even if rows were inserted. (checked on MySQL 5.0.85 linux and php 5.2.9-2 windows). However mysqli->sqlstate returns no error if statement was executed successfully.
<?php
if ($mysqli->affected_rows!=-1){
    echo "success";// for "INSERT IGNORE" statements will not occur if there were any duplicate key errors ignored during execution of the query
}
else {
    echo "fail";// "INSERT IGNORE" statements causing any duplicate key errors (however ignored) lead to mysqli->affected_rows equal -1
}

// Example below works for "INSERT IGNORE" stattements, too
if ($mysqli->sqlstate=="00000"){
    echo "success";
}
else {
    echo "fail";
}
?>