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

说明

面向对象风格

int|string $mysqli->affected_rows;

过程化风格

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.

参数

mysql: 仅以过程化样式：由 mysqli_connect() 或 mysqli_init() 返回的 mysqli 对象。

返回值

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.

注意:
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.

示例

示例 #1 $mysqli->affected_rows example

面向对象风格

<?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");

过程化风格

<?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");

以上示例会输出：

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

参见

mysqli_num_rows() - Gets the number of rows in the result set
mysqli_info() - 返回最近执行的 SQL 语句的信息

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用户贡献的备注 3 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
)