PDOStatement::fetch

Fetches the next row from a result set

&reftitle.description; public `mixed` `PDOStatement::fetch` `int` `mode` PDO::FETCH_DEFAULT `int` `cursorOrientation` PDO::FETCH_ORI_NEXT `int` `cursorOffset` 0

Fetches a row from a result set associated with a PDOStatement object. The `mode` parameter determines how PDO returns the row.

&reftitle.parameters;

`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, mapping the columns of the result set to named properties in the class, and calling the constructor afterwards, unless `PDO::FETCH_PROPS_LATE` is also given. If `mode` includes PDO::FETCH_CLASSTYPE (e.g. `PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE`) then the name of the class is determined from a 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.

&reftitle.returnvalues;

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.

&reftitle.errors; &pdo.errors;
&reftitle.examples;

### 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";
    ?>

&example.outputs;

    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

### 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);
    ?>

&example.outputs;

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

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

### 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. If `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();
    ?>

&example.outputs.similar;

    I am Alice.
    I am Alice.
    I don't have a name yet.
    I am Bob.

&reftitle.seealso;

- `PDO::prepare`
- `PDOStatement::execute`
- `PDOStatement::fetchAll`
- `PDOStatement::fetchColumn`
- `PDOStatement::fetchObject`
- `PDOStatement::setFetchMode`