mysqli::$affected_rows

mysqli_affected_rows

(PHP 5, PHP 7, PHP 8)

mysqli::$affected_rows -- mysqli_affected_rows — Retorna o número de linhas afetadas pela operação MySQL anterior

Descrição

Estilo orientado a objetos

int|string $mysqli->affected_rows;

Estilo procedural

mysqli_affected_rows(mysqli $mysql): int|string

Retorna o número de linhas afetadas pelo último comando INSERT, UPDATE, REPLACE ou DELETE. Funciona como mysqli_num_rows() para consultas SELECT.

Parâmetros

mysql: Somente no estilo procedural: Um objeto mysqli retornado por mysqli_connect() ou mysqli_init()

Valor Retornado

Um inteiro maior do que zero indica o número de linhas afetadas ou obtidas. Zero indica que nenhum registro foi atualizado por uma declaração UPDATE, nenhuma linha correspondeu à claúsula WHERE na consulta ou que nenhuma consulta foi executada ainda. -1 indica que a consulta retornou um erro ou que mysqli_affected_rows() foi chamada para uma consulta SELECT sem buffer.

Nota:
Se o número de linhas afetadas for maior do que o maior valor inteiro (PHP_INT_MAX), o número de linhas afetadas será retornado como uma string.

Exemplos

Exemplo #1 Exemplo de $mysqli->affected_rows

Estilo orientado a objetos

<?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");

Estilo procedural

<?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");

Os exemplos acima produzirão:

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

Veja Também

mysqli_num_rows() - Obtém o número de linhas no resultado
mysqli_info() - Recupera informação sobre a recente consulta executada

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Notas Enviadas por Usuários (em inglês) 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/

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