[edit] Last updated: Fri, 10 Feb 2012

PDOStatement::fetch

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

PDOStatement::fetch — 結果セットから次の行を取得する

説明

mixed PDOStatement::fetch ([ int $fetch_style [, int $cursor_orientation = PDO::FETCH_ORI_NEXT [, int $cursor_offset = 0 ]]] )

PDOStatementオブジェクトに関連付けられた結果セットから1行取得します。 fetch_style パラメータは、PDO がその行をどの様に返すかを決定します。

パラメータ

fetch_style

次のレコードを呼び出し元に返す方法を制御します。この値は、PDO::FETCH_* 定数のどれかで、デフォルトは PDO::ATTR_DEFAULT_FETCH_MODE の値 (そのデフォルトは PDO::FETCH_BOTH) です。

PDO::FETCH_ASSOC: は、結果セットに返された際のカラム名で添字を付けた配列を返します。
PDO::FETCH_BOTH (デフォルト): 結果セットに返された際のカラム名と 0 で始まるカラム番号で添字を付けた配列を返します。
PDO::FETCH_BOUND: TRUE を返し、結果セットのカラムの値を PDOStatement::bindColumn() メソッドでバインドされた PHP 変数に代入します。
PDO::FETCH_CLASS: 結果セットのカラムがクラス内の名前付けされたプロパティにマッピングされている、要求されたクラスの新規インスタンスを返します。 fetch_style に PDO::FETCH_CLASSTYPE が含まれている場合 (例: PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE) は、最初のカラムの値からクラス名を決定します。
PDO::FETCH_INTO: 結果セットのカラムがクラス内の名前付けされたプロパティにマッピングされている要求された既存インスタンスを更新します。
PDO::FETCH_LAZY: PDO::FETCH_BOTH とPDO::FETCH_OBJの組合せで、オブジェクト変数名を作成します。
PDO::FETCH_NUM: 結果セットに返された際の 0 から始まるカラム番号を添字とする配列を返します。
PDO::FETCH_OBJ: 結果セットに返された際のカラム名と同名のプロパティを有する匿名のオブジェクトを返します。

cursor_orientation

スクロール可能なカーソルを表す PDOStatement オブジェクトの場合、この値により呼び出し側に返される行を定義します。この値は、PDO::FETCH_ORI_* 定数のどれかとする必要があり、 PDO::FETCH_ORI_NEXT がデフォルトとなっています。 PDOStatement に対してスクロール可能なカーソルを要求するためには、 PDO::prepare() を用いて SQL ステートメントを準備する際、 PDO::CURSOR_SCROLL に PDO::ATTR_CURSOR 属性を設定する必要があります。

offset

スクロール可能なカーソルを表すPDOStatementオブジェクトの場合で、 cursor_orientationパラメータが PDO::FETCH_ORI_ABSに設定された場合、この値により取得される結果セットの行の絶対位置が指定されます。

スクロール可能なカーソルを表すPDOStatementオブジェクトの場合で、 cursor_orientationパラメータが PDO::FETCH_ORI_RELに設定された場合、この値は、 PDOStatement::fetch() がコールされる前のカーソルの位置を基準として取得する行の位置を指定します。

返り値

この関数が成功した場合の返り値は、取得形式によって異なります。失敗した場合は常に FALSE を返します。

例

例1 異なる取得方法で行を取得する


<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();

/* Exercise PDOStatement::fetch styles */
print("PDO::FETCH_ASSOC: ");
print("Return next row as an array indexed by column name\n");
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
print("\n");

print("PDO::FETCH_BOTH: ");
print("Return next row as an array indexed by both column name and number\n");
$result = $sth->fetch(PDO::FETCH_BOTH);
print_r($result);
print("\n");

print("PDO::FETCH_LAZY: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_LAZY);
print_r($result);
print("\n");

print("PDO::FETCH_OBJ: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_OBJ);
print $result->NAME;
print("\n");
?>

上の例の出力は以下となります。

PDO::FETCH_ASSOC: Return next row as an array indexed by column name
Array
(
    [NAME] => apple
    [COLOUR] => red
)

PDO::FETCH_BOTH: Return next row as an array indexed by both column name and number
Array
(
    [NAME] => banana
    [0] => banana
    [COLOUR] => yellow
    [1] => yellow
)

PDO::FETCH_LAZY: Return next row as an anonymous object with column names as properties
PDORow Object
(
    [NAME] => orange
    [COLOUR] => orange
)

PDO::FETCH_OBJ: Return next row as an anonymous object with column names as properties
kiwi

例2 スクロール可能なカーソルで行を取得する


<?php
function readDataForwards($dbh) {
  $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY BET';
  try {
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
    $stmt->execute();
    while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_NEXT)) {
      $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n";
      print $data;
    }
    $stmt = null;
  }
  catch (PDOException $e) {
    print $e->getMessage();
  }
}
function readDataBackwards($dbh) {
  $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY bet';
  try {
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
    $stmt->execute();
    $row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_LAST);
    do {
      $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n";
      print $data;
    } while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_PRIOR));
    $stmt = null;
  }
  catch (PDOException $e) {
    print $e->getMessage();
  }
}

print "Reading forwards:\n";
readDataForwards($conn);

print "Reading backwards:\n";
readDataBackwards($conn);
?>

上の例の出力は以下となります。

Reading forwards:
21    10    5
16    0     5
19    20    10

Reading backwards:
19    20    10
16    0     5
21    10    5

参考

PDO::prepare() - 文を実行する準備を行い、文オブジェクトを返す
PDOStatement::execute() - プリペアドステートメントを実行する
PDOStatement::fetchAll() - 全ての結果行を含む配列を返す
PDOStatement::fetchColumn() - 結果セットの次行から単一カラムを返す
PDOStatement::fetchObject() - 次の行を取得し、それをオブジェクトとして返す
PDOStatement::setFetchMode() - この文に対するデフォルトのフェッチモードを設定する

PDOStatement::fetchAll

PDOStatement::execute

[edit] Last updated: Fri, 10 Feb 2012

add a note User Contributed Notes PDOStatement::fetch

Alex 06-Sep-2011 08:32


It seems that if you do a $statement->query() with an INSERT statement and after that a $statement->fetch() you will get an exception saying: SQLSTATE[HY000]: General error.

henry at henrysmith dot org 06-Aug-2011 03:24


Someone's already pointed out that PDO::CURSOR_SCROLL isn't supported by the SQLite driver. It's also worth noting that it's not supported by the MySQL driver either.



In fact, if you try to use scrollable cursors with a MySQL statement, the PDO::FETCH_ORI_ABS parameter and the offset given to fetch() will be silently ignored. fetch() will behave as normal, returning rows in the order in which they came out of the database.



It's actually pretty confusing behaviour at first. Definitely worth documenting even if only as a user-added note on this page.

Ome Ko 20-Jun-2011 10:46


Don't do 

if($objStatement->fetch()) return $objStatement->fetch(); 



You want   

if($blah=$objStatement->fetch()) return $blah;



Trust me on this one.

public at grik dot net 24-Nov-2010 08:10


When fetching an object, the constructor of the class is called after the fields are populated by default.





PDO::FETCH_PROPS_LATE is used to change the behaviour and make it work as expected - constructor be called _before_ the object fields will be populated with the data.





sample:





<?php


$a = $PDO->query('select id from table');


$a->setFetchMode(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE, 'ClassName');


$obj = $a->fetch();


?>





http://bugs.php.net/bug.php?id=53394

Negative Black 24-Aug-2010 04:50


When fetching multiple rows into an object. It is necessary to clone the objects returned by the PDOStatement::fetch() operation. Otherwise you will just get a list of pointers to the object located inside the statement, containing the information of the last row.



Example:

<?php

$stmt = $pdoLink->prepare("SELECT * FROM `table`;");

$stmt->setFetchMode(PDO::FETCH_INTO, new myClass());

$stmt->execute();



// Assuming there are multiple rows in the table.

while ($object = $stmt->fetch()) {

    $result[] = clone $object;

}



var_dump($result);

?>

Typer85 at gmail dot com 01-Feb-2010 08:03


Here is quick note for developers that use the PDO SQLite Driver:



The PDO SQLite driver does not support cursors, so using the PDO::CURSOR_SCROLL Attribute, will not work when using the PDO SQLite driver. For example:



<?php



// Assuming $Handle Is a PDO Handle.

$Statement = $Handle->query( $sqlStatement , array( PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL ) );



?>



What is even worse is that PDO::prepare will NOT throw an Exception when it fails to prepare the query, even when the error mode is set to throw Exceptions, and will instead return a Boolean False!



Not only do I consider this a poor design choice, but also its a real shame that this is not documented anywhere in the manual -- in fact the manual is not clear on what Attributes are supported by which drivers and which are not so developers are left to play a classic game of guess.



I hope this saves some developers some headaches.



Good Luck,

Typer85 at gmail dot com 26-Jan-2010 10:52


Just thought I would point out something interesting that caught my eye.



Once you retrieve a PDOStatement, whether for a prepared statement or a normal result set, the connection status of your PDO handle is no longer taken into consideration!



The PHP Manual clearly states that to open a PDO connection, create a new Instance of the PDO Class. To close a PDO connection, destroy the Instance, possibly by setting it to a Null Reference. The PDO Instance in this case is your handle.



Here is the interesting part. If you close the PDO connection, as described above, you can still continue to either execute a prepared statement or iterate through a result set!



For example, the following code will work perfectly fine:



<?php



// Open Handle.

$Handle = new PDO( 'mysql:host=localhost; dbname=LOG' , 'root' );

$Handle->setAttribute( PDO::ATTR_ERRMODE , PDO::ERRMODE_EXCEPTION );



// Prepare Statement.

$Statement = $Handle->prepare( "SELECT * FROM ERROR" );



// Close Handle.

$Handle =  null;



// Execute Statement. Amazing How There Is No Problem Even Though The Connection Is Closed!

$Statement->execute();



// Iterate Result. Again, Amazing How There Is No Problem!

while( $row = $Statement->fetch( PDO::FETCH_BOTH , PDO::FETCH_ORI_NEXT ) ) {

}



?>



You do not even need to prepare a statement. A native query also has no problems, like the following code:



<?php



// Open Handle.

$Handle = new PDO( 'mysql:host=localhost; dbname=LOG' , 'root' );

$Handle->setAttribute( PDO::ATTR_ERRMODE , PDO::ERRMODE_EXCEPTION );



// Query Statement.

$Statement = $Handle->query( "SELECT * FROM ERROR" );



// Close Handle.

$Handle =  null;



// Iterate Result.

$Statement->fetchAll( );



?>



I am not sure if this is a bug or not but its a big gottcha for developers coming from other envrionments, such as .NET or even those PHP developers used to using the native database functions before PDO came around.



For example, using the native mysql_* Functions, the following will not work:



<?php



mysql_connect( "localhost" , "root");

mysql_select_db( "LOG" );

mysql_close( );

mysql_query( "SELECT * FROM ERROR" );



?>



Good Luck,

dj UNDERSCORE robe AT hotmail DOT com 21-Jan-2010 09:33


A word of caution regarding fh at ez dot no's note: as of PHP 5.2.12 the constructor is called *before* the data is set in FETCH_CLASS mode.  The previous behaviour seems to be considered a bug (http://bugs.php.net/bug.php?id=49521), so don't rely on it.

lod 16-Jul-2008 03:33


A quick one liner to get the first entry returned.  This is nice for very basic queries.



<?php

$count = current($db->query("select count(*) from table")->fetch());

?>php

lozitskiys at gmail dot com 08-Jul-2008 11:21


I spent some hours trying to find out how to manipulate with BLOB fields using PDO.



Remember that you can't retreive BLOB data using something like this :



<?php

$sql = 'SELECT * FROM sometable LIMIT 1';

$stmt = $dbh->prepare($sql);

$stmt->execute();

$stmt->setAttribute(PDO::FETCH_ASSOC);

$row = $stmt->fetch();



$myFile = $row['file'];

?>



Instead of this you should try following approach:



<?php

$sql = "SELECT mime, file FROM sometable LIMIT 1"; 

$stmt = $dbh->prepare($sql); 

$stmt->execute(); 



$stmt->bindColumn(1, $mime,); 

$stmt->bindColumn(2, $file, PDO::PARAM_LOB); 



$stmt->fetch(); 



header('Content-type: '.$mime);

print $file; 



?>

josh 28-Apr-2008 06:02


Note that PDO::ATTR_STRINGIFY_FETCHES will NOT work for the MySQL driver. MySQL will always return strings because that is the behaviour of the core mysql PHP extension. See http://bugs.php.net/bug.php?id=44341

daltenho at yahoo dot com 28-Jan-2008 02:17


As an alternative to marcini's suggestion:



You can use:



        $dbh->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true);



...on your PDO connection object to allow query buffering in MySQL. This will eliminate the problem of re-preparing an unclosed statement object.

Gerard van Beek 27-Oct-2007 07:42


If you to use a new instance of a class for a record you can use:



<?php

include_once("user.class");

$sth = $db->prepare("SELECT * FROM user WHERE id = 1");



/* create instance automatically */

$sth->setFetchMode( PDO::FETCH_CLASS, 'user');

$sth->execute();

$user = $sth->fetch( PDO::FETCH_CLASS );

$sth->closeCursor();

print ($user->id);



/* or create an instance yourself and use it */

$user= new user();

$sth->setFetchMode( PDO::FETCH_INTO, $user);

$sth->execute();

$user= $sth->fetch( PDO::FETCH_INTO );

$sth->closeCursor();

print ($user->id);

?>

BaBna 16-Aug-2007 06:52


When you do a SELECT query for one row, and want to check if it's there, you don't need to count the fetchAll() result, you can just check if $result->fetch() is true:

<?php

$bbnq = sprintf("SELECT login

FROM users

WHERE id = %u",27);

try

    { $req = $db_bbn->query($bbnq); }

catch (Exception $e)

    { bbnf_pdo_error($e,__FILE__,__LINE__); }

if ( $r = $req->fetch() )

    { echo "This query has a row result"; }

else

    { echo "This query has an empty result"; }

?>

marcini 01-Apr-2007 10:41


Be careful with fetch() when you use prepared statements and MySQL (I don`t know how it is with other databases). Fetch won`t close cursor and won`t let you send any other query, even if your result set has only one row, . 

If you use $statement->fetch(), you will also have to use $statement->closeCursor() afterwards, to be albe to execute another query.

Alternatively you can use $statement->fetchAll() without $statement->closeCursor().

terry at bitsoup dot com 02-Mar-2006 05:46


WARNING:

fetch() does NOT adhere to SQL-92 SQLSTATE standard when dealing with empty datasets.



Instead of setting the errorcode class to 20 to indicate "no data found", it returns a class of 00 indicating success, and returns NULL to the caller.



This also prevents the exception mechainsm from firing.



Programmers will need to explicitly code tests for empty resultsets after any fetch*() instead of relying on the default behavior of the RDBMS.



I tried logging this as a bug, but it was dismissed as "working as intended". Just a head's up.

avinoamr at gmail dot com 19-Jan-2006 07:48


Note that using the FETCH_CLASS mechanism does NOT trigger the class's constructor! You must explicity instantiate the class to use it's constructor behavior.

fh at ez dot no 24-Nov-2005 05:13


I can also add that the constructor is run _after_ the data is set on the object if yo use PDO::FETCH_CLASS.

fh at ez dot no 24-Nov-2005 04:58


If you want to use PDO::FETCH_CLASS you need to set it up with setFetchMode first like so:

        $stmt->setFetchMode( PDO::FETCH_CLASS, 'classType', array( 'parameters to constructor' );

        $object = $stmt->fetch( PDO::FETCH_CLASS );

If you ommit this PHP will segfault.

aledmb at gmail dot com 21-Oct-2005 04:22


note that fetch constants are not included in the PDO class for PHP versions prior to 5.1

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