mysql_affected_rows
(PHP 4, PHP 5, PECL mysql:1.0)
mysql_affected_rows — Возвращает число затронуиых прошлой операцией рядов.
Описание
mysql_affected_rows() возвращает количество рядов, затронутых последним INSERT, UPDATE, DELETE запросом к серверу, на который ссылается указатель link_identifier . Если ресурс не указан, функция использует последнее, успешное соединение, выполненное с помощью функции mysql_connect().
Замечание: При использовании транзакций mysql_affected_rows() надо вызывать после INSERT, UPDATE, DELETE запроса, но не после подтверждения.
Если последний запрос был DELETE без указания WHERE и, соответственно, таблица была очищена, функция вернёт ноль (0).
Замечание: При использовании UPDATE, MySQL не обновит колонки, уже содержащие новое значение. Вследствие этого, функция mysql_affected_rows() не всегда возвращает количество рядов, подошедших по условия, только количество рядов, обновлённых запросом.
mysql_affected_rows() не работает с SELECT -- только с запросами, модифицирующими таблицу. Чтобы получить количество рядов, возвращённых SELECT-запросом, используйте функцию mysql_num_rows().
Если последний запрос был неудачным, функция вернёт -1.
Пример #1 DELETE-запрос
<?php
/* соединямеся с базой данных */
mysql_pconnect("localhost", "mysql_user", "mysql_password") or
die("Could not connect: " . mysql_error());
mysql_select_db("mydb");
/* здесь функция вернёт корректное число удалённых записей */
mysql_query("DELETE FROM mytable WHERE id < 10");
printf ("Records deleted: %d\n", mysql_affected_rows());
/* без указания WHERE в запросе, функция всегда возвращает 0 */
mysql_query("DELETE FROM mytable");
printf ("Records deleted: %d\n", mysql_affected_rows());
?>
Вышеописанный пример выдаст следующий результат:
Records deleted: 10 Records deleted: 0
Пример #2 UPDATE-запрос
<?php
/* соединямеся с базой данных */
mysql_pconnect("localhost", "mysql_user", "mysql_password") or
die("Could not connect: " . mysql_error());
mysql_select_db("mydb");
/* Обновляем ряды */
mysql_query("UPDATE mytable SET used=1 WHERE id < 10");
printf ("Updated records: %d\n", mysql_affected_rows());
mysql_query("COMMIT");
?>
Вышеописанный пример выдаст следующий результат:
Updated Records: 10
См. также mysql_num_rows(), mysql_info().
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Коментарии
It works also for REPLACE query,returning:0 if the record it's already updated (0 record modified),
1 if the record it's new (1 record inserted),
2 if the record it's updated (2 operations: 1 deletion+ 1 insertion)
Using OPTIMIZE TABLE will also return true.So, if you want to check the numbers of deleted records, use mysql_affected_rows() before OPTIMIZE TABLE
SCENARIO
1. You're using MySQL 4.1x with foreign keys.
2. You have table t2 linked to table t1 by a CASCADE ON DELETE foreign key.
3. t2 has a UNIQUE key so that duplicate records are unacceptable.
3. You have a REPLACE query on t1 followed by an INSERT query on t2 and expect the second query to fail if there's an attempted insert of a duplicate record.
PROBLEM
You notice that the second query is not failing as you had expected even though the record being inserted is an exact duplicate of a record previously inserted.
CAUSE
When the first query (the REPLACE query) deletes a record from t1 in the first stage of the REPLACE operation, it cascades the delete to the record that would be duplicated in t2. The second query then does not fail because the "duplicate" record is no longer a duplicate, as the original one has just been deleted.
I see that when try to use mysql_affected_rows() with "mysql_pconnect(...)" without link indetifier as param in "mysql_affected_rows()" the result is allways -1.When use link identifier "mysql_affected_rows($this_sql_connection)" - everything is Fine. This is is on PHP Version 5.2.0
Hope that this was helpfull for somebody
If you use "INSERT INTO ... ON DUPLICATE KEY UPDATE" syntax, mysql_affected_rows() will return you 2 if the UPDATE was made (just as it does with the "REPLACE INTO" syntax) and 1 if the INSERT was.
So if you use one SQL request to insert several rows at a time, and some are inserted, some are just updated, you won't get the real count.
Here's a little function I've been using for a while now, pass it two parameters (action command (1 or 0 see notes)) and a sql statement.
It returns a simple line which shows the length of time taken to action the query, the status of the query (0= query not actioned, you can set this value for testing, 1=success qry executed successfully, -1= failed, there was a problem with the sql statement) the number of lines affected by that query and the sql statement itself.
I've found this invaluable when trying to tie down large amounts of updates to a table, using this you can easily see where a query was successfully executed and the number of rows are affected, or where there are problems and a statement has failed for example.
<?php
function dosql($action,$sql){
# assuming you have setup a link to your database entitled $link
# action = 1 run this query
# action = 0 don't run, just return sql statement
$start = getmtime();
if($action==1){
$result = mysql_query($sql);
$affectedrows = "[".mysql_affected_rows($link)."]";
}
return "[".number_format((getmtime()-$start),3)."][$action]: $sql\n";
mysql_free_result($result);
}
?>
Example output:
[0.072][1][80]: UPDATE MYTABLE SET FIELD = 1;
[0.106][1][758]: UPDATE ANOTHERTABLE SET FIELD = 2;
[0.006][-1][0]: UPDATER ANOTHERTABLE SET FIELD = 2;
The output shows:
[Timetaken][result]][lines affected]
The result will be either -1, 0 or 1, -1 means there's a problem with the sql statement, 1 means it executed correctly, 0 means it wasn't executed.
There are no rows affected by an update with identical data.So here is one very ugly solution for these cases:
<?
function mysql_matched_rows() {
$_kaBoom=explode(' ',mysql_info());
return $_kaBoom[2];
}
?>
I was just testing "INSERT INTO ... ON DUPLICATE KEY UPDATE" syntax, on PHP 5.3.29 and mysql_affected_rows() was returning either 2 for updated row, 1 for inserted new row, and also 0, which was not documented, evidently when nothing was inserted. I was inserting a single row.In the case of INSERT where a row/slot had been previously deleted, making an uncollapsed hole in the table, and the record being inserted fills that empty row/slot, that is to say, the inserted data did not create a new row/slot/space, then this may explain why a zero result is returned by this function.calling mysql_affected_rows(null)
is not the same that calling mysql_affected_rows()
So, if you have a $link variable that could be null, you must write
if($link)
$n=mysql_affected_rows($link);
else
$n=mysql_affected_rows();
Note that when the CLIENT_FOUND_ROWS connection flag was used, affected_rows returns the number of rows matched by the WHERE condition of an UPDATE query, even if the query doesn't actually change those rows. I.e. for
INSERT INTO t(id, val) VALUES (1, 'x');
UPDATE t SET val = 'x' WHERE id = 1;
the number of affected rows will be 0 normally but 1 with CLIENT_FOUND_ROWS.