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(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)
PDOStatement->rowCount — Returns the number of rows affected by the last SQL statement
PDOStatement::rowCount() returns the number of rows affected by the last DELETE, INSERT, or UPDATE statement executed by the corresponding PDOStatement object.
If the last SQL statement executed by the associated PDOStatement was a SELECT statement, some databases may return the number of rows returned by that statement. However, this behaviour is not guaranteed for all databases and should not be relied on for portable applications.
Returns the number of rows.
Beispiel #1 Return the number of deleted rows
PDOStatement::rowCount() returns the number of rows affected by a DELETE, INSERT, or UPDATE statement.
<?php
/* Delete all rows from the FRUIT table */
$del = $dbh->prepare('DELETE FROM fruit');
$del->execute();
/* Return number of rows that were deleted */
print("Return number of rows that were deleted:\n");
$count = $del->rowCount();
print("Deleted $count rows.\n");
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
Deleted 9 rows.
Beispiel #2 Counting rows returned by a SELECT statement
For most databases, PDOStatement::rowCount() does not return the number of rows affected by a SELECT statement. Instead, use PDO::query() to issue a SELECT COUNT(*) statement with the same predicates as your intended SELECT statement, then use PDOStatement::fetchColumn() to retrieve the number of rows that will be returned. Your application can then perform the correct action.
<?php
$sql = "SELECT COUNT(*) FROM fruit WHERE calories > 100";
if ($res = $conn->query($sql)) {
/* Check the number of rows that match the SELECT statement */
if ($res->fetchColumn() > 0) {
/* Issue the real SELECT statement and work with the results */
$sql = "SELECT name FROM fruit WHERE calories > 100";
foreach ($conn->query($sql) as $row) {
print "Name: " . $row['NAME'] . "\n";
}
}
/* No rows matched -- do something else */
else {
print "No rows matched the query.";
}
}
$res = null;
$conn = null;
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
apple banana orange pear
It appears that rowCount behavior is different on Mysql 5.0 vs 5.1. Here's the test I ran:
<?php
$db = new PDO('mysql:host=localhost;dbname=test','test','test');
$sql = "SELECT 1";
$st = $db->prepare($sql);
$st->execute();
print_r($st->rowCount());
?>
Mysql 5.0.45, PHP 5.2.5 returned 1
Mysql 5.1.30, PHP 5.1.6 returned 0
I know... I need to test against same php versions... buy I'm getting lazy...
My rowCount() workaround & how it's used:
<?php
class MyPDO extends PDO {
private $queryString;
public function query(/* ... */) {
$args = func_get_args();
$this->queryString = func_get_arg(0);
return call_user_func_array(array(&$this, 'parent::query'), $args);
}
public function rowCount() {
$regex = '/^SELECT\s+(?:ALL\s+|DISTINCT\s+)?(?:.*?)\s+FROM\s+(.*)$/i';
if (preg_match($regex, $this->queryString, $output) > 0) {
$stmt = parent::query("SELECT COUNT(*) FROM {$output[1]}", PDO::FETCH_NUM);
return $stmt->fetchColumn();
}
return false;
}
}
$pdo = new MyPDO("sqlite::memory:");
$result = $pdo->query("SELECT row1, row2 FROM table WHERE something = 5");
if ($pdo->rowCount() > 0) {
echo "{$result['row1']}, {$result['row2']}";
}
?>
As of SQLite 3.x, the SQLite API itself changed and now all queries are implemented using "statements". Because of this, there is no way for PDO to know the rowCount of a SELECT result because the SQLite API itself doesn't offer this ability.
As a workaround, I created my own rowCount() function - it's a bit of a hack and hasn't been fully tested yet (I don't know how it will work when using JOINs in SELECTs, etc...), but at least alleviates the necessity for SELECT COUNT(*)'s everywhere in your code.
I would have preferred if it were possible to overload the rowCount() function from PDOStatement, but I don't think it's possible (or I don't know how to do it). There's also potential room for a bit more security ensuring that $queryString is wiped clean after other query()s so that you don't get a bad result, etc...
The actual code should be posted in the above/below post (max post limits, argh!). If others wish to extend/perfect this method, please keep me posted with an email as to what you've done.
It'd better to use SQL_CALC_FOUND_ROWS, if you only use MySQL. It has many advantages as you could retrieve only part of result set (via LIMIT) but still get the total row count.
code:
<?php
$db = new PDO(DSN...);
$db->setAttribute(array(PDO::MYSQL_USE_BUFFERED_QUERY=>TRUE));
$rs = $db->query('SELECT SQL_CALC_FOUND_ROWS * FROM table LIMIT 5,15');
$rs1 = $db->query('SELECT FOUND_ROWS()');
$rowCount = (int) $rs1->fetchColumn();
?>
The rowCount method does not seem to work with pdo_sqlite, maybe because it will not support forward-only cursors:
<?php
error_reporting(E_ALL+E_NOTICE);
$dsn = 'sqlite::memory:';
$pdo = new PDO($dsn);
$pdo->exec('CREATE TABLE foo(id varchar(11) NOT NULL, PRIMARY KEY(id))');
$pdo->exec("INSERT INTO foo(id) VALUES ('ffs')");
$sqlGet = 'SELECT * FROM foo WHERE id=:id';
$stmt = $pdo->prepare($sqlGet);
$id = 'ffs';
$stmt->bindParam(':id', $id, PDO::PARAM_STR);
$stmt->execute();
var_dump($stmt->rowCount(), count($stmt->fetchAll()));
?>
which outputs: 0 1
http://php.net/manual/en/function.sqlite-num-rows.php says sqlite_num_rows() cannot be used on unbuffered results; the explanation to the failure of the rowCount() method is probably along the same lines.
The workaround would be to use the count() function on a fetched result, but it might not be as efficient.
To Matt,
PDO is very similar in design to Perl's DBI which does allow you to set driver specific attributes such as mysql_client_found_rows=1 as part of the DSN.
PDO has a setAttribute() method, but afaik there is no
MYSQL_ATTR_CLIENT_FOUND_ROWS constant (yet). Hopefully some PDO developer will patch it in one day.
Setting that (at least in Perl and C) will make rowCount() return the number of rows selected for the update, not just the number of rows actually updated.
Great, while using MySQL5, the only way to get the number of rows after doing a PDO SELECT query is to either execute a separate SELECT COUNT(*) query (or to do count($stmt->fetchAll()), which seems like a ridiculous waste of overhead and programming time.
Another gripe I have about PDO is its inability to get the value of output parameters from stored procedures in some DBMSs, such as SQL Server.
I'm not so sure I'm diggin' PDO yet.
hipska at mac dot com : what you say is not correct.
The resulting $fruits cannot be used as an array, and count($fruits) always equals 1.
The confusion is however understandable, since foreach ($fruits->query($query) as $row){} will work, as with any array.
The most efficient way to retrieve number of rows found by SELECT in a portable application is probably to make a condition :
- Check that the current database system (get its name via getAttribute()), is one where rowCount() returns the number of rows found
1) If it does, there you have it
2) If it does not, execute an extra COUNT query.
In some case you need to know how many row are retrieved from a select query (i.e to page a result set) you can use:
$totalRows = count($resultSet->fetchAll());
It works on MySQL 5.0.18 and PHP 5.1
For large resultsets the method described below is not very efficient. It is better to do a select COUNT(*).
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