mysqli::$affected_rows

mysqli_affected_rows

(PHP 5, PHP 7, PHP 8)

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

Descrizione

Stile orientato agli oggetti

int|string $mysqli->affected_rows;

Stile procedurale

mysqli_affected_rows(mysqli $mysql): int|string

Returns the number of rows affected by the last INSERT, UPDATE, REPLACE or DELETE query. Works like mysqli_num_rows() for SELECT statements.

Elenco dei parametri

link: Solo nello stile procedurale: un identificatore restituito da mysqli_connect() o mysqli_init()

Valori restituiti

An integer greater than zero indicates the number of rows affected or retrieved. Zero indicates that no records were 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 or that mysqli_affected_rows() was called for an unbuffered SELECT query.

Nota:
If the number of affected rows is greater than the maximum int value (PHP_INT_MAX), the number of affected rows will be returned as a string.

Esempi

Example #1 $mysqli->affected_rows example

Stile orientato agli oggetti

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* 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);

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

Stile procedurale

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* 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));

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

I precedenti esempi visualizzeranno:

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

Vedere anche:

mysqli_num_rows() - Gets the number of rows in the result set
mysqli_info() - Retrieves information about the most recently executed query

Improve This Page

Learn How To Improve This Page • Submit a Pull Request • Report a Bug

＋add a note

User Contributed Notes 5 notes

down

Anonymous ¶

13 years ago

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

down

Jacques Amar ¶

7 years ago

While using prepared statements, even if there is no result set (Like in an UPDATE or DELETE), you still need to store the results before affected_rows returns the actual number:

<?php
$del_stmt->execute();
$del_stmt->store_result();
$count = $del_stmt->affected_rows;
?>

Otherwise things will just be frustrating ..

down

Michael ¶

10 years ago

If you need to know specifically whether the WHERE condition of an UPDATE operation failed to match rows, or that simply no rows required updating you need to instead check mysqli::$info.

As this returns a string that requires parsing, you can use the following to convert the results into an associative array.

Object oriented style:

<?php
    preg_match_all ('/(\S[^:]+): (\d+)/', $mysqli->info, $matches); 
    $info = array_combine ($matches[1], $matches[2]);
?>

Procedural style:

<?php
    preg_match_all ('/(\S[^:]+): (\d+)/', mysqli_info ($link), $matches); 
    $info = array_combine ($matches[1], $matches[2]);
?>

You can then use the array to test for the different conditions

<?php
    if ($info ['Rows matched'] == 0) {
        echo "This operation did not match any rows.\n";
    } elseif ($info ['Changed'] == 0) {
        echo "This operation matched rows, but none required updating.\n";
    }

    if ($info ['Changed'] < $info ['Rows matched']) {
        echo ($info ['Rows matched'] - $info ['Changed'])." rows matched but were not changed.\n";
    }
?>

This approach can be used with any query that mysqli::$info supports (INSERT INTO, LOAD DATA, ALTER TABLE, and UPDATE), for other any queries it returns an empty array.

For any UPDATE operation the array returned will have the following elements:

Array
(
    [Rows matched] => 1
    [Changed] => 0
    [Warnings] => 0
)

down

mishell dot mercer at gmail dot com ¶

3 months ago

Do note that if you have turned off autocommit, and plan to do multiple actions before the commit, $affected_rows only works per statement. This means if, for example, you want to run multiple INSERT statements and tally all rows inserted after they are commited, a running counter will need to be implemented.

// start the count
$count = 0;

// turn off autocommit
$mysqli->autocommit(FALSE);
$mysqli->begin_transaction;

// insert a couple items
$query = "
    INSERT INTO users ('id','username','email') 
    VALUES (1, 'userguy', 'userguy@mail.com'), (2, 'some_user', 'some_user@ymail.com')
";
$mysqli->query($query);
echo $mysqli->affected_rows;  // 2 - correct
$count += $mysqli->affected_rows;  // add to the count

// insert one more
$query = "
    INSERT INTO users ('id','username','email') 
    VALUES (3, 'anotherone', 'anotherone@mail.com')
";
$mysqli->query($query);
$count += $mysqli->affected_rows;

// insert one more
$query = "
    INSERT INTO users ('id','username','email') 
    VALUES (4, 'thefourth', 'thefourth@gmail.com')
";
$mysqli->query($query);
$count += $mysqli->affected_rows;

// commit these statements to the database
$mysqli->commit();

echo $mysqli->affected_rows;  // 1 - only counts the last statement run
echo "Actual count: ".$count;  // 4

down

-3

lucgommans.nl ¶

1 year ago

Under the hood, this calls into mysql_affected_rows (1). The MariaDB function ROW_COUNT() mentions (2) that it is the equivalent of that C API function. These two lines, SQL followed by PHP, should be equivalent:

SELECT ROW_COUNT();
$db->affected_rows;

I found this useful to double check things in an SQL prompt, to make sure affected_rows is reflecting what I expect (changed rows as opposed to matched rows in an update statement), which indeed it did.

1. https://github.com/php/php-src/blob/1521cafee29e23ca147ec777f3770a7ac46c6880/ext/mysqli/mysqli_api.c#L36-L49
2. https://mariadb.com/kb/en/row_count/

＋add a note