mysqli_affected_rows

Gets the number of affected rows in a previous MySQL operation (PHP 5)
int mysqli_affected_rows ( mysqli link )

Procedural style:

Object oriented style (property):

mysqli {
  int affected_rows ;
}

mysqli_affected_rows() returns the number of rows affected by the last INSERT, UPDATE, or DELETE query associated with the provided link parameter. If the last query was invalid, this function will return -1.

注意:

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

The mysqli_affected_rows() function only works with queries which modify a table. In order to return the number of rows from a SELECT query, use the mysqli_num_rows() function instead.

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.

注意:

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

例 1246. 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();
}

/* 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();
?>

例 1247. Procedural style

<?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);
?>

上例将输出:

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