PDOStatement
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PDOStatement::rowCount

(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)

PDOStatement::rowCount — Returns the number of rows affected by the last SQL statement

说明

int PDOStatement::rowCount ( void )

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.

返回值

Returns the number of rows.

范例

Example #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");
?>

以上例程会输出：

Return number of rows that were deleted:
Deleted 9 rows.

Example #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;
?>

以上例程会输出：

apple
banana
orange
pear

参见

PDOStatement
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PHP手册
PHP手册 - N: Returns the number of rows affected by the last SQL statement

用户评论:

nuggez at gmail dot com (14-Mar-2012 03:52)

<?php

$sql = 'SELECT * FROM users WHERE point< :point';
$sth = $this->db->prepare($sql);

/* Bindparam to point */
$sth->execute(Array(':point' => 20));
$data = $sth->fetchAll();

/* Get the number of rows that match the SELECT statement */
$count = sizeof($data); /* or count($data) */

/* Print how many records found */
echo $count.' record found';

/* List data */
if ($count > 0) {
    foreach ($data as $value) {
        echo $value['Name'].'<br />';
     }
  }
}
?>

leandro at marquesini dot com (03-Jan-2012 06:04)

To display information only when the query is not empty, I do something like this:

<?php
    $sql = 'SELECT model FROM cars';
    $stmt = $db->prepare($sql);
    $stmt->execute();
   
    if ($data = $stmt->fetch()) {
        do {
            echo $data['model'] . '<br>';
        } while ($data = $stmt->fetch());
    } else {
        echo 'Empty Query';
    }
?>

dcahh at gmx dot de (19-Aug-2011 02:53)

It's pretty obvious, but might save one or the other from bug tracking...

Alltough rowCount ist returned by the statement, one has to execute the statement before rowCount returns any results...

Does not work
<?php
    $statement = $dbh->prepare('SELECT FROM fruit');
    $count = $statement->rowCount();
?>

Works
<?php
    $statement = $dbh->prepare('SELECT FROM fruit');
    $statement->execute();
    $count = $statement->rowCount();
?>

Ome Ko (16-Jul-2011 08:08)

When updating a Mysql table with identical values nothing's really affected so rowCount will return 0. As Mr. Perl below noted this is not always preferred behaviour and you can change it yourself since PHP 5.3.

Just create your PDO object with
<? php
$p = new PDO($dsn, $u, $p, array(PDO::MYSQL_ATTR_FOUND_ROWS => true));
?>
and rowCount() will tell you how many rows your update-query actually found/matched.

php at alishabeth dot com (21-Jan-2009 01:15)

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...

e dot sand at elisand dot com (19-Nov-2008 07:32)

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']}";
}
?>

e dot sand at elisand dot com (19-Nov-2008 07:30)

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.

gunnrosebutpeace at gmail dot com (03-Jun-2008 11:19)

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();
?>

Anonymous (26-Dec-2007 12:10)

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.

Mr. Perl (14-Nov-2007 03:06)

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.

Matt (07-Oct-2007 05:22)

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.