mysqli_result::fetch_assoc

mysqli_fetch_assoc

(PHP 5, PHP 7, PHP 8)

mysqli_result::fetch_assoc -- mysqli_fetch_assoc — Fetch the next row of a result set as an associative array

Descrizione

Stile orientato agli oggetti

public mysqli_result::fetch_assoc(): array|null|false

Stile procedurale

mysqli_fetch_assoc(mysqli_result $result): array|null|false

Fetches one row of data from the result set and returns it as an associative array. Each subsequent call to this function will return the next row within the result set, or null if there are no more rows.

If two or more columns of the result have the same name, the last column will take precedence and overwrite any previous data. To access multiple columns with the same name, mysqli_fetch_row() may be used to fetch the numerically indexed array, or aliases may be used in the SQL query select list to give columns different names.

Nota: I nomi dei campi restituiti da questa funzione sono case-sensitive.

Nota: Questa funzione imposta i campio NULL al valore PHP null.

Elenco dei parametri

result: Solo nello stile procedurale: un identificatore di resultset restituito da mysqli_query(), mysqli_store_result() o mysqli_use_result().

Valori restituiti

Returns an associative array representing the fetched row, where each key in the array represents the name of one of the result set's columns, null if there are no more rows in the result set, o false in caso di fallimento.

Esempi

Example #1 mysqli_result::fetch_assoc() example

Stile orientato agli oggetti

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$query = "SELECT Name, CountryCode FROM City ORDER BY ID DESC";

$result = $mysqli->query($query);

/* fetch associative array */
while ($row = $result->fetch_assoc()) {
    printf("%s (%s)\n", $row["Name"], $row["CountryCode"]);
}

Stile procedurale

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = mysqli_connect("localhost", "my_user", "my_password", "world");

$query = "SELECT Name, CountryCode FROM City ORDER BY ID DESC";

$result = mysqli_query($mysqli, $query);

/* fetch associative array */
while ($row = mysqli_fetch_assoc($result)) {
    printf("%s (%s)\n", $row["Name"], $row["CountryCode"]);
}

The above examples will output something similar to:

Pueblo (USA)
Arvada (USA)
Cape Coral (USA)
Green Bay (USA)
Santa Clara (USA)

Example #2 Comparison of mysqli_result iterator and mysqli_result::fetch_assoc() usage

mysqli_result can be iterated using foreach. The result set will always be iterated from the first row, regardless of the current position.

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$query = 'SELECT Name, CountryCode FROM City ORDER BY ID DESC';

// Using iterators
$result = $mysqli->query($query);
foreach ($result as $row) {
    printf("%s (%s)\n", $row["Name"], $row["CountryCode"]);
}

echo "\n==================\n";

// Not using iterators
$result = $mysqli->query($query);
while ($row = $result->fetch_assoc()) {
    printf("%s (%s)\n", $row["Name"], $row["CountryCode"]);
}

Il precedente esempio visualizzerà qualcosa simile a:

Pueblo (USA)
Arvada (USA)
Cape Coral (USA)
Green Bay (USA)
Santa Clara (USA)

==================
Pueblo (USA)
Arvada (USA)
Cape Coral (USA)
Green Bay (USA)
Santa Clara (USA)

Vedere anche:

mysqli_fetch_array() - Fetch the next row of a result set as an associative, a numeric array, or both
mysqli_fetch_column() - Fetch a single column from the next row of a result set
mysqli_fetch_row() - Fetch the next row of a result set as an enumerated array
mysqli_fetch_object() - Fetch the next row of a result set as an object
mysqli_query() - Performs a query on the database
mysqli_data_seek() - Adjusts the result pointer to an arbitrary row in the result

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User Contributed Notes 3 notes

down

Miller ¶

11 years ago

I often like to have my results sent elsewhere in the format of an array (although keep in mind that if you just plan on traversing through the array in another part of the script, this extra step is just a waste of time).

This is my one-liner for transforming a mysqli_result set into an array.
<?php
$sql = new MySQLi($host, $username, $password, $database);

$result = $sql->query("SELECT * FROM `$table`;");
for ($set = array (); $row = $result->fetch_assoc(); $set[] = $row);
print_r($set);
?>

Outputs:
Array
(
    [0] => Array
        (
            [id] => 1
            [field2] => a
            [field3] => b
        ),
    [1] => Array
        (
            [id] => 2
            [field2] => c
            [field3] => d
        )
)

I use other variations to adapt to the situation, i.e. if I am selecting only one field:
<?php
$sql = new MySQLi($host, $username, $password, $database);
$result = $sql->query("SELECT `field2` FROM `$table`;");
for ($set = array (); $row = $result->fetch_assoc(); $set[] = $row['field2']);
print_r($set);
?>
Outputs:
Array
(
    [0] => a
    [1] => c
)

Or, to make the array associative with the primary index (code assumes primary index is the first field in the table):
<?php
$sql = new MySQLi($host, $username, $password, $database);
$result = $sql->query("SELECT * FROM `$table`;");
for ($set = array (); $row = $result->fetch_assoc(); $set[array_shift($row)] = $row);
print_r($set);
?>
Outputs:
Array
(
    [1] => Array
        (
            [field2] => a
            [field3] => b
        ),
    [2] => Array
        (
            [field2] => c
            [field3] => d
        )
)

down

james dot phx at gmail dot com ¶

13 years ago

IMPORTANT NOTE:



If you were used to using code like this:



<?php

while(false !== ($row = mysql_fetch_assoc($result)))

{

    //...

}

?>



You must change it to this for mysqli:



<?php

while(null !== ($row = mysqli_fetch_assoc($result)))

{

    //...

}

?>



The former will cause your script to run until max_execution_time is reached.

down

Enrique Garcia ¶

1 year ago

There is a difference between MariaDB and MySQL(>5.4) whether the input parameter (mysqli object) has data or is empty (it comes from a previus query).
-MariaDB:  you get an exception:
Fatal error: Uncaught TypeError: mysqli_fetch_assoc(): Argument #1 ($result) must be of type mysqli_result
-MySQL: you can continue, in spite of not having data in the mysqli object.

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