(PHP 5, PHP 7, PHP 8)
mysqli::$affected_rows -- mysqli_affected_rows — Gets the number of affected rows in a previous MySQL operation
面向对象风格
过程化风格
   Returns the number of rows affected by the last INSERT,
   UPDATE, REPLACE or 
   DELETE query.
   Works like mysqli_num_rows() for
   SELECT statements.
  
   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 #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");
以上例程会输出:
Affected rows (INSERT): 984 Affected rows (UPDATE): 168 Affected rows (DELETE): 815 Affected rows (SELECT): 169