(PHP 5 >= 5.1.0, PHP 7, PHP 8, PECL pdo >= 0.1.0)
PDOStatement::fetch — Fetches the next row from a result set
$mode = PDO::FETCH_DEFAULT, int $cursorOrientation = PDO::FETCH_ORI_NEXT, int $cursorOffset = 0): mixed
Fetches a row from a result set associated with a PDOStatement object. The
mode parameter determines how PDO returns
the row.
mode
Controls how the next row will be returned to the caller. This value
must be one of the PDO::FETCH_* constants,
defaulting to value of PDO::ATTR_DEFAULT_FETCH_MODE
(which defaults to PDO::FETCH_BOTH).
PDO::FETCH_ASSOC: returns an array indexed by column
name as returned in your result set
PDO::FETCH_BOTH (default): returns an array indexed by
both column name and 0-indexed column number as returned in your
result set
PDO::FETCH_BOUND: returns true and assigns the
values of the columns in your result set to the PHP variables to which
they were bound with the PDOStatement::bindColumn()
method
PDO::FETCH_CLASS: returns a new instance of the
requested class. The object is initialized by mapping the columns of
the result set to properties in the class. This occurs before the
constructor is called, allowing properties to be populated regardless
of their visibility or whether they are marked as readonly.
If a property does not exist in the class, the magic __set()
method will be invoked if it exists; otherwise, a dynamic public
property will be created. However, when PDO::FETCH_PROPS_LATE
is also given, the constructor is called before
the properties are populated. If mode includes
PDO::FETCH_CLASSTYPE (e.g.
PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE), the name
of the class is determined from the value of the first column.
PDO::FETCH_INTO: updates an existing instance
of the requested class, mapping the columns of the result set to
named properties in the class
PDO::FETCH_LAZY: combines
PDO::FETCH_BOTH and PDO::FETCH_OBJ,
and is returning a PDORow object
which is creating the object property names as they are accessed.
PDO::FETCH_NAMED: returns an array with the same
form as PDO::FETCH_ASSOC, except that if there are
multiple columns with the same name, the value referred to by that
key will be an array of all the values in the row that had that
column name
PDO::FETCH_NUM: returns an array indexed by column
number as returned in your result set, starting at column 0
PDO::FETCH_OBJ: returns an anonymous object with
property names that correspond to the column names returned in your
result set
PDO::FETCH_PROPS_LATE: when used with
PDO::FETCH_CLASS, the constructor of the class is
called before the properties are assigned from the respective column
values.
cursorOrientation
For a PDOStatement object representing a scrollable cursor, this
value determines which row will be returned to the caller. This value
must be one of the PDO::FETCH_ORI_* constants,
defaulting to PDO::FETCH_ORI_NEXT. To request a
scrollable cursor for your PDOStatement object, you must set the
PDO::ATTR_CURSOR attribute to
PDO::CURSOR_SCROLL when you prepare the SQL
statement with PDO::prepare() .
cursorOffset
For a PDOStatement object representing a scrollable cursor for which
the cursorOrientation parameter is set to
PDO::FETCH_ORI_ABS, this value specifies the
absolute number of the row in the result set that shall be fetched.
For a PDOStatement object representing a scrollable cursor for which
the cursorOrientation parameter is set to
PDO::FETCH_ORI_REL, this value specifies the
row to fetch relative to the cursor position before
PDOStatement::fetch() was called.
The return value of this function on success depends on the fetch type. In
all cases, false is returned on failure or if there are no more rows.
Emits an error with level E_WARNING if the attribute PDO::ATTR_ERRMODE is set
to PDO::ERRMODE_WARNING .
Throws a PDOException if the attribute PDO::ATTR_ERRMODE
is set to PDO::ERRMODE_EXCEPTION .
Example #1 Fetching rows using different fetch styles
<?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 a PDORow 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 $result->name;
print "\n";
?>The above example will output:
PDO::FETCH_ASSOC: Return next row as an array indexed by column name Array ( [name] => apple [colour] => red ) PDO::FETCH_BOTH: Return next row as an array indexed by both column name and number Array ( [name] => banana [0] => banana [colour] => yellow [1] => yellow ) PDO::FETCH_LAZY: Return next row as a PDORow object with column names as properties PDORow Object ( [name] => orange [colour] => orange ) PDO::FETCH_OBJ: Return next row as an anonymous object with column names as properties kiwi
Example #2 Fetching rows with a scrollable cursor
<?php
function readDataForwards($dbh) {
$sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY BET';
$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 $data;
}
}
function readDataBackwards($dbh) {
$sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY bet';
$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 = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_PRIOR));
}
print "Reading forwards:\n";
readDataForwards($conn);
print "Reading backwards:\n";
readDataBackwards($conn);
?>The above example will output:
Reading forwards: 21 10 5 16 0 5 19 20 10 Reading backwards: 19 20 10 16 0 5 21 10 5
Example #3 Construction order
When objects are fetched via PDO::FETCH_CLASS , the object
properties are assigned first, and then the constructor of the class is
invoked. However, when PDO::FETCH_PROPS_LATE is also given,
this order is reversed, i.e. first the constructor is called, and
afterwards the properties are assigned.
<?php
class Person
{
private $name;
public function __construct()
{
$this->tell();
}
public function tell()
{
if (isset($this->name)) {
echo "I am {$this->name}.\n";
} else {
echo "I don't have a name yet.\n";
}
}
}
$sth = $dbh->query("SELECT * FROM people");
$sth->setFetchMode(PDO::FETCH_CLASS, 'Person');
$person = $sth->fetch();
$person->tell();
$sth->setFetchMode(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE, 'Person');
$person = $sth->fetch();
$person->tell();
?>The above example will output something similar to:
I am Alice. I am Alice. I don't have a name yet. I am Bob.
WARNING:
fetch() does NOT adhere to SQL-92 SQLSTATE standard when dealing with empty datasets.
Instead of setting the errorcode class to 20 to indicate "no data found", it returns a class of 00 indicating success, and returns NULL to the caller.
This also prevents the exception mechainsm from firing.
Programmers will need to explicitly code tests for empty resultsets after any fetch*() instead of relying on the default behavior of the RDBMS.
I tried logging this as a bug, but it was dismissed as "working as intended". Just a head's up.If no record, this function will also return false.
I think that is not very good...Someone's already pointed out that PDO::CURSOR_SCROLL isn't supported by the SQLite driver. It's also worth noting that it's not supported by the MySQL driver either.
In fact, if you try to use scrollable cursors with a MySQL statement, the PDO::FETCH_ORI_ABS parameter and the offset given to fetch() will be silently ignored. fetch() will behave as normal, returning rows in the order in which they came out of the database.
It's actually pretty confusing behaviour at first. Definitely worth documenting even if only as a user-added note on this page.When using PDO::FETCH_COLUMN in a while loop, it's not enough to just use the value in the while statement as many examples show:
<?php
while ($row = $stmt->fetch(PDO::FETCH_COLUMN)) {
print $row;
}
?>
If there are 5 rows with values 1 2 0 4 5, then the while loop above will stop at the third row printing only 1 2. The solution is to either explicitly test for false:
<?php
while (($row = $stmt->fetch(PDO::FETCH_COLUMN)) !== false) {
print $row;
}
?>
Or use foreach with fetchAll():
<?php
foreach ($stmt->fetchAll(PDO::FETCH_COLUMN) as $row) {
print $row;
}
?>
Both will correctly print 1 2 0 4 5.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());
?>phpWhen 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 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,A prior poster indicated that this function returns a NULL when there are no results. This is not true. This function returns an empty array. fetchAll() returns the same.
Also, the documentation specifies what happens on "failure", but doesn't indicate what constitutes a "failure". A "failure" could be where the function returns no results; that is, the query "failed". However, a "failure" is apparently a situation where the PDO error functions would reveal a "failure", as in illegal SQL syntax, or a query on a table which doesn't exist, etc. An empty result is not a "failure". Maybe that's obvious to everyone else, but it wasn't to me.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);
?>Because MySQL does not currently support the use of cursors, the $cursor_offset feature cannot work when using PDO to access a MySQL database.
If you are tring to arbitrarily access a specific record or group of records in a MySQL database recordset, you might want to consider using the LIMIT clause of the SELECT statement to achieve this e.g. LIMIT 5,3 to return just the 6th,7th & 8th records - 3 records starting at index 5 (which is the 6th record).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.I can also add that the constructor is run _after_ the data is set on the object if yo use PDO::FETCH_CLASS.this is just On reminder note about Second parameter -cursor_oriantation-
PDO::FETCH_ORI_NEXT :-
Fetch the next row in the result set. Valid only for scrollable cursors.
PDO::FETCH_ORI_PRIOR :-
Fetch the previous row in the result set. Valid only for scrollable cursors.
PDO::FETCH_ORI_FIRST :-
Fetch the first row in the result set. Valid only for scrollable cursors.
PDO::FETCH_ORI_LAST :-
Fetch the last row in the result set. Valid only for scrollable cursors.
PDO::FETCH_ORI_ABS :-
Fetch the requested row by row number from the result set. Valid only for scrollable cursors.
PDO::FETCH_ORI_REL :-
Fetch the requested row by relative position from the current position of the cursor in the result set. Valid only for scrollable cursors.When using a PDOStatement with the fetch mode set to FETCH_CLASS, fetch will return false if no rows were found.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().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.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;
?>I could use PDO::FETCH_COLUMN to retrieve the first column from result.
$ps->fetch( PDO::FETCH_COLUMN );
Worked on Postgresql with PHP 5.3.10.note that fetch constants are not included in the PDO class for PHP versions prior to 5.1Note 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 Note that this way, the "fetch mode" will get "overwritten", and PDO::FETCH_PROPS_LATE won't be applied:
<?php
$sth = $db->prepare("SELECT * FROM user WHERE id = 1");
$sth->setFetchMode( PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE, 'user');
$sth->execute();
$user = $sth->fetch( PDO::FETCH_CLASS );
$sth->closeCursor();
?>
Instead, you should leave the parameter area for the fetch() method empty, like this (if you want to set the fetch mode with the setFetchMode() method):
<?php
$sth = $db->prepare("SELECT * FROM user WHERE id = 1");
$sth->setFetchMode( PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE, 'user');
$sth->execute();
$user = $sth->fetch();
$sth->closeCursor();
?>Be careful when using PDO::FETCH_LAZY. It adds an additional field called queryString. I'm not sure if this a bug or not. I'm using version 5.6.17 in Debian Jessie.
Query: 'select 1,2,3'
$row=$smt->fetch(PDO::FETCH_OBJ);
var_dump($row);
object(stdClass)#6 (3) {
["1"]=>
string(1) "1"
["2"]=>
string(1) "2"
["3"]=>
string(1) "3"
}
$row=$smt->fetch(PDO::FETCH_LAZY);
var_dump($row);
object(PDORow)#3 (4) {
["queryString"]=>
string(12) "select 1,2,3"
["1"]=>
string(1) "1"
["2"]=>
string(1) "2"
["3"]=>
string(1) "3"
}