PDOStatement::fetchAll
(PHP 5 >= 5.1.0, PHP 7, PECL pdo >= 0.1.0)
PDOStatement::fetchAll — Возвращает массив, содержащий все строки результирующего набора
Описание
$fetch_style
[, mixed $fetch_argument
[, array $ctor_args = array()
]]] )Список параметров
-
fetch_style -
Определяет содержимое возвращаемого массива. Подробней можно узнать из документации к методу PDOStatement::fetch(). По умолчанию параметр принимает значение
PDO::ATTR_DEFAULT_FETCH_MODE(которое в свою очередь имеет умолчаниеPDO::FETCH_BOTH)Чтобы извлечь значения только одного столбца, передайте в качестве значения этого параметра константу
PDO::FETCH_COLUMN. С помощью параметраcolumn-indexможно задать столбец, из которого требуется извлечь данные.Если требуется извлечь только уникальные строки одного столбца, нужно передать побитовое ИЛИ констант
PDO::FETCH_COLUMNиPDO::FETCH_UNIQUE.Чтобы получить ассоциативный массив строк сгруппированный по значениям определенного столбца, нужно передать побитовое ИЛИ констант
PDO::FETCH_COLUMNиPDO::FETCH_GROUP. -
fetch_argument -
Смысл этого аргумента зависит от значения параметра
fetch_style:-
PDO::FETCH_COLUMN: Будет возвращен указанный столбец. Индексация столбцов начинается с 0. -
PDO::FETCH_CLASS: Будет создан и возвращен новый объект указанного класса. Свойствам объекта будут присвоены значения столбцов, имена которых совпадут с именами свойств. -
PDO::FETCH_FUNC: Будут возвращены результаты вызовов указанной функции. Данные каждой строки результирующего набора будут передаваться в эту функцию.
-
-
ctor_args -
Аргументы конструктора класса. Для случаев, когда параметру
fetch_styleприсвоено значениеPDO::FETCH_CLASS.
Возвращаемые значения
PDOStatement::fetchAll() возвращает массив, содержащий все
оставшиеся строки результирующего набора. Массив представляет каждую строку
либо в виде массива значений одного столбца, либо в виде объекта, имена свойств
которого совпадают с именами столбцов. В случае, если нет результатов, то
будет возвращен пустой массив. В случае ошибки возвращается FALSE.
Использование этого метода для извлечения строк больших результирующих наборов может пагубно сказаться на производительности системы и сетевых ресурсов. Вместо извлечения всех данных и их обработки в PHP рекомендуется использовать встроенные средства СУБД. Например, использование выражений WHERE и ORDER BY языка SQL может уменьшить размеры результирующего набора.
Примеры
Пример #1 Извлечение всех оставшихся строк результирующего набора
<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
/* Извлечение всех оставшихся строк результирующего набора */
print("Извлечение всех оставшихся строк результирующего набора:\n");
$result = $sth->fetchAll();
print_r($result);
?>
Результатом выполнения данного примера будет что-то подобное:
Извлечение всех оставшихся строк результирующего набора:
Array
(
[0] => Array
(
[NAME] => pear
[0] => pear
[COLOUR] => green
[1] => green
)
[1] => Array
(
[NAME] => watermelon
[0] => watermelon
[COLOUR] => pink
[1] => pink
)
)
Пример #2 Извлечение всех значений одного столбца результирующего набора
В следующем примере показано, как извлечь из результирующего набора значения только одного столбца, даже если строки содержат значения нескольких столбцов.
<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
/* Извлечение всех значений первого столбца */
$result = $sth->fetchAll(PDO::FETCH_COLUMN, 0);
var_dump($result);
?>
Результатом выполнения данного примера будет что-то подобное:
Array(3)
(
[0] =>
string(5) => apple
[1] =>
string(4) => pear
[2] =>
string(10) => watermelon
)
Пример #3 Группировка строк по значениям одного столбца
В следующем примере показано, как получить ассоциативный массив строк результирующего набора, сгруппированных по значениям указанного столбца. Массив содержит три ключа: значения apple и pear являются массивами, содержащими два разных цвета; в тоже время watermelon будет массивом, содержащим только один цвет.
<?php
$insert = $dbh->prepare("INSERT INTO fruit(name, colour) VALUES (?, ?)");
$insert->execute(array('apple', 'green'));
$insert->execute(array('pear', 'yellow'));
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
/* Группируем записи по значениям первого столбца */
var_dump($sth->fetchAll(PDO::FETCH_COLUMN|PDO::FETCH_GROUP));
?>
Результатом выполнения данного примера будет что-то подобное:
array(3) {
["apple"]=>
array(2) {
[0]=>
string(5) "green"
[1]=>
string(3) "red"
}
["pear"]=>
array(2) {
[0]=>
string(5) "green"
[1]=>
string(6) "yellow"
}
["watermelon"]=>
array(1) {
[0]=>
string(5) "green"
}
}
Пример #4 Создание объекта для каждой строки
В следующем примере показано поведение метода в режиме выборки
PDO::FETCH_CLASS.
<?php
class fruit {
public $name;
public $colour;
}
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
$result = $sth->fetchAll(PDO::FETCH_CLASS, "fruit");
var_dump($result);
?>
Результатом выполнения данного примера будет что-то подобное:
array(3) {
[0]=>
object(fruit)#1 (2) {
["name"]=>
string(5) "apple"
["colour"]=>
string(5) "green"
}
[1]=>
object(fruit)#2 (2) {
["name"]=>
string(4) "pear"
["colour"]=>
string(6) "yellow"
}
[2]=>
object(fruit)#3 (2) {
["name"]=>
string(10) "watermelon"
["colour"]=>
string(4) "pink"
}
}
Пример #5 Вызов функции для каждой строки
В следующем примере показано поведение метода в режиме выборки
PDO::FETCH_FUNC.
<?php
function fruit($name, $colour) {
return "{$name}: {$colour}";
}
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
$result = $sth->fetchAll(PDO::FETCH_FUNC, "fruit");
var_dump($result);
?>
Результатом выполнения данного примера будет что-то подобное:
array(3) {
[0]=>
string(12) "apple: green"
[1]=>
string(12) "pear: yellow"
[2]=>
string(16) "watermelon: pink"
}
Смотрите также
- PDO::query() - Выполняет SQL запрос и возвращает результирующий набор в виде объекта PDOStatement
- PDOStatement::fetch() - Извлечение следующей строки из результирующего набора
- PDOStatement::fetchColumn() - Возвращает данные одного столбца следующей строки результирующего набора
- PDO::prepare() - Подготавливает запрос к выполнению и возвращает ассоциированный с этим запросом объект
- PDOStatement::setFetchMode() - Задает режим выборки по умолчанию для объекта запроса
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения для работы с базами данных
- Уровни абстракции
- Объекты данных PHP
- Функция PDOStatement::bindColumn() - Связывает столбец с PHP переменной
- Функция PDOStatement::bindParam() - Привязывает параметр запроса к переменной
- Функция PDOStatement::bindValue() - Связывает параметр с заданным значением
- Функция PDOStatement::closeCursor() - Закрывает курсор, переводя запрос в состояние готовности к повторному запуску
- Функция PDOStatement::columnCount() - Возвращает количество столбцов в результирующем наборе
- Функция PDOStatement::debugDumpParams() - Вывод информации о подготовленной SQL команде в целях отладки
- Функция PDOStatement::errorCode() - Определяет SQLSTATE код соответствующий последней операции объекта PDOStatement
- PDOStatement::errorInfo
- Функция PDOStatement::execute() - Запускает подготовленный запрос на выполнение
- Функция PDOStatement::fetch() - Извлечение следующей строки из результирующего набора
- Функция PDOStatement::fetchAll() - Возвращает массив, содержащий все строки результирующего набора
- Функция PDOStatement::fetchColumn() - Возвращает данные одного столбца следующей строки результирующего набора
- Функция PDOStatement::fetchObject() - Извлекает следующую строку и возвращает ее в виде объекта
- Функция PDOStatement::getAttribute() - Получение значения атрибута запроса PDOStatement
- Функция PDOStatement::getColumnMeta() - Возвращает метаданные столбца в результирующей таблице
- Функция PDOStatement::nextRowset() - Переход к следующему набору строк в результате запроса
- Функция PDOStatement::rowCount() - Возвращает количество строк, модифицированных последним SQL запросом
- Функция PDOStatement::setAttribute() - Присваивает атрибут объекту PDOStatement
- Функция PDOStatement::setFetchMode() - Задает режим выборки по умолчанию для объекта запроса
Коментарии
Note, that you can use PDO::FETCH_COLUMN|PDO::FETCH_GROUP pair only while selecting two columns, not like DB_common::getAssoc(), when grouping is set to true.If no rows have been returned, fetchAll returns an empty array.There is also another fetch mode supported on Oracle and MSSQL:
PDO::FETCH_ASSOC
> fetches only column names and omits the numeric index.
If you would like to return all columns from an sql statement with column keys as table headers, it's as simple as this:
<?php
$dbh = new PDO("DS", "USERNAME", "PASSWORD");
$stmt = $dbh->prepare("SELECT * FROM tablename");
$stmt->execute();
$arrValues = $stmt->fetchAll(PDO::FETCH_ASSOC);
// open the table
print "<table wdith=\"100%\">\n";
print "<tr>\n";
// add the table headers
foreach ($arrValues[0] as $key => $useless){
print "<th>$key</th>";
}
print "</tr>";
// display data
foreach ($arrValues as $row){
print "<tr>";
foreach ($row as $key => $val){
print "<td>$val</td>";
}
print "</tr>\n";
}
// close the table
print "</table>\n";
?>
PHP fetchAll Data From SQL Server 2005
if field's data type is varchar(nvarchar), only fetch 255 chars. but the "text" data type is ok.
so, notice! to change the 'varchar' or 'nvarchar' (length > 255) to 'text' data type..
hope to help u.
<?php
$user = 'sa';
$pass = 'pass';
$conn = new PDO('mssql:host=127.0.0.1; dbname=tempdb;', $user, $pass);
$mainSQL = "SELECT field_varchar, field_text FROM table1";
$sth = $conn->prepare($mainSQL);
$sth->setFetchMode(PDO::FETCH_ASSOC);
$sth->execute();
$retRows = $sth->fetchAll();
// the field_varchar field only to fetch 255 chars(max)
// the field_text is ok.
var_dump($retRows);
unset($sth); unset($conn);
?>
When passing PDO::FETCH_CLASS as the first argument, this method will accept the class name as the second option:
<?php
$query = $pdo->prepare($sql);
$result = $query->execute($values);
if ($result && $query->rowCount() > 0) {
$records = $query->fetchAll(PDO::FETCH_CLASS, 'Some_Class');
// $record is now an array of Some_Class objects
}
?>
- Davey
PLEASE BE AWARE: If you do an OUTER LEFT JOIN and set PDO FetchALL to PDO::FETCH_ASSOC, any primary key you used in the OUTER LEFT JOIN will be set to a blank if there are no records returned in the JOIN.
For example:
<?php
//query the product table and join to the image table and return any images, if we have any, for each product
$sql = "SELECT * FROM product, image
LEFT OUTER JOIN image ON (product.product_id = image.product_id)";
$array = $stmt->fetchAll(PDO::FETCH_ASSOC);
print_r($array);
?>
The resulting array will look something like this:
Array
(
[0] => Array
(
[product_id] =>
[notes] => "this product..."
[brand] => "Best Yet"
...
The fix is to simply specify your field names in the SELECT clause instead of using the * as a wild card, or, you can also specify the field in addition to the *. The following example returns the product_id field correctly:
<?php
$sql = "SELECT *, product.product_id FROM product, image
LEFT OUTER JOIN image ON (product.product_id = image.product_id)";
$array = $stmt->fetchAll(PDO::FETCH_ASSOC);
print_r($array);
?>
The resulting array will look something like this:
Array
(
[0] => Array
(
[product_id] => 3
[notes] => "this product..."
[brand] => "Best Yet"
...
In method body:
return $pstmt->fetchAll() or die("bad");
will not return correct value, but "1" instead.
Interestingly enough, when you use fetchAll, the constructor for your object is called AFTER the properties are assigned. For example:
<?php
class person {
public $name;
function __construct() {
$this->name = $this->name . " is my name.";
}
}
# set up select from a database here with PDO
$obj = $STH->fetchALL(PDO::FETCH_CLASS, 'person');
?>
Will result in ' is my name' being appended to all the name columns. However if you call it slightly differently:
<?php
$obj = $obj = $STH->fetchAll(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE, 'person');
?>
Then the constructor will be called before properties are assigned. I can't find this documented anywhere, so I thought it would be nice to add a note here.
Error:
SQLSTATE[HY000]: General error: 2014 Cannot execute queries while other unbuffered queries are active. Consider using PDOStatement::fetchAll(). Alternatively, if your code is only ever going to run against mysql, you may enable query buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY attribute.
If you're using something like:
while ($row = $query->fetchObject()) {
[...]
}
try using this instead:
$rows = $query->fetchAll(PDO::FETCH_CLASS, 'ArrayObject');
foreach ($rows as $row) {
[...]
}
Note that fetchAll() can be extremely memory inefficient for large data sets. My memory limit was set to 160 MB this is what happened when I tried:
<?php
$arr = $stmt->fetchAll();
// Fatal error: Allowed memory size of 16777216 bytes exhausted
?>
If you are going to loop through the output array of fetchAll(), instead use fetch() to minimize memory usage as follows:
<?php
while ($arr = $stmt->fetch()) {
echo round(memory_get_usage() / (1024*1024),3) .' MB<br />';
// do_other_stuff();
}
// Last line for the same query shows only 28.973 MB usage
?>
If you use the PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE flags to map columns to object properties, fetchAll() will use any __set() method your object has when carrying out the mapping.If you are trying to call PDOStatement::fetchAll and is not getting the result set as expected (empty instead), check if you called PDOStatement::execute first.
Remember PDOStatement::fetchAll does not execute the query, it just mounts the array.
:)
If you want to use PDO::FETCH_CLASS but don't like that all the values are of the type string, you can always use the __construct function of the class specified to convert them to a different type.
Another way is using mysqlnd, but it seems I had to recompile PHP for that.
<?php
class Cdr {
public $a; // int
public $b; // float
public $c; // string
public function __construct() {
$this->a = intval($this->a);
$this->b = floatval($this->b);
}
}
// ...
$arrCdrs = $objSqlStatement->fetchAll(PDO::FETCH_CLASS, 'Cdr');
?>
If you want to fetch rows as an object for which you have not defined a class, you can do:<?php
$result = $q->fetchAll(PDO::FETCH_OBJ);
?>
Getting foreach to play nicely with some data from PDO FetchAll()
I was not understanding to use the $value part of the foreach properly, I hope this helps someone else.
Example:
<?php
$stmt = $this->db->prepare('SELECT title, FMarticle_id FROM articles WHERE domain_name =:domain_name');
$stmt->bindValue(':domain_name', $domain);
$stmt->execute();
$article_list = $stmt->fetchAll(PDO::FETCH_ASSOC);
?>
which gives:
array (size=2)
0 =>
array (size=2)
'title' => string 'About Cats Really Long title for the article' (length=44)
'FMarticle_id' => string '7CAEBB15-6784-3A41-909A-1B6D12667499' (length=36)
1 =>
array (size=2)
'title' => string 'another cat story' (length=17)
'FMarticle_id' => string '0BB86A06-2A79-3145-8A02-ECF6EA5C405C' (length=36)
Then use:
<?php
foreach ($article_list as $row => $link) {
echo '<a href="'. $link['FMarticle_id'].'">' . $link['title']. '</a></br>';
}
?>
There may be some user who needs to upgrade their MySQL class to PDO class. The way of fetching results were changed from while loop into a foreach loop. For the people who wish to fetch the results in a while loop, here is a simple trick.
<?php
$db = new DB();
$query = $db->prepare("SELECT * FROM CPUCategory");
$query = $db->execute();
$result = $db->fetchAll();
var_dump($result);
?>
The Output will be:
array(2) {
[0]=> array(2) {
["ccatid"]=> int(1)
["ccatname"]=> string(5) "Intel"
}
[1]=> array(2) {
["ccatid"]=> int(2)
["ccatname"]=> string(3) "AMD"
}
}
Never look like the output of old function.
[ORIGINAL STYLE] mysql_fetch_array($query)
[ MYSQL CLASS] $db->fetch_array($query)
And you may give up.
But there is a simple way to use while loop to fetch the results.
<?php
$db = new DB();
$query = $db->prepare("SELECT * FROM CPUCategory");
$query = $db->execute();
$result = $db->fetchAll();
$row = array_shift($result);
// If you need to fetch them now, put it in a while loop just like below:
// while($row = array_shift($result)) { ... }
var_dump($row);
?>
The Output will be in a single array with while loop returns TRUE:
array(2) {
["ccatid"]=> int(1)
["ccatname"]=> string(5) "Intel"
}
So after fetching this row, while loop runs again and fetch the next row until all row has fetched, then the while loop will return false. (Just like the old function did)
When you need to upgrade to PDO class, not much code needs to be modified and remember.
Something missing in the doc.
If for instance you try to fetchAll(PDO::CLASS, "Class") it sometimes return an array of objects with NULL values, but the count of objects fetched correspond to table rows.
In this way works fine:
fetchAll(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE, "Class");
For example
$stm = $pdo->prepare("SELECT * FROM Fruit");
$stm->execute();
$stm->fetchAll(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE, "Fruit");
I was having trouble with returning PDO query results in arrays, due to the structure of the results of those queries (query array with arrays for results inside). Now when executing a fetchAll() on a query you get the following:
Array ( [0] = Array ( [key1] => "value1", [key2] => "value2") [1] = Array( [key1] => "value1", [key2] => "value2") )
This is a smaller array, but return results in a HUGE database this way and it quickly becomes IMPPOSIBRU to read out the array given.
This is where the glorious foreach comes in! We all know the basic writing of a foreach (foreach ($array as $key => $value) {...}), but with query results there's a twist, as both the $key AND $value variables are arrays, where $key is the array of the query containing the result arrays and $value is/are the result array(s) themselves.
So in this foreach we have to talk directly to $value to get our results! This would look something like this:
<?php
foreach ($query as $key => $value) {
return $value["key2"];
}
?>
This already does the job, but to return them in arrays we have to change our return code a little bit, like so:
<?php
foreach ($query as $key => $value) {
return array (
"key1" => $value["key1"],
"key2" => $value["key2"]
);
}
?>
This foreach loops through the query array, just like the firs one, but the return code just doesn't return the keys representing the result arrays ($key) and returns only keys from inside the result arrays, stored in $value. This gives us an array looking like this:
Array ( [key1] => "value1", [key2] => "value2")
This should return all the values in your array, if written properly. I'm still having problems with the foreach not returning ALL results, but this note was mainly to show how it can be returned in an array.
I still don't understand why FETCH_KEY_PAIR is not documented here (http://php.net/manual/fr/pdo.constants.php), because it could be very useful!
<?php
var_dump($pdo->query('select id, name from table')->fetchAll(PDO::FETCH_KEY_PAIR));
?>
This will display:
array(2) {
[2]=>
string(10) "name2"
[5]=>
string(10) "name5"
}
Be careful when using PDO::FETCH_COLUMN with PDO::FETCH_GROUP. By default, results are grouped by first column (index 0) and second column (index 1) is returned. But, if you provide fetch argument, it wouldn't affect returned column, but grouping column. If grouping column is set explicitly , first columns is returned instead of second.
<?php
$insert = $dbh->prepare("INSERT INTO people(id, gender) VALUES (?, ?)");
$insert->execute(array('2', 'female'));
$insert->execute(array('3', 'female'));
$insert->execute(array('4', 'female'));
$insert->execute(array('5', 'male'));
$insert->execute(array('6', 'male'));
$sth = $dbh->prepare("SELECT gender, id FROM people");
$sth->execute();
/* Group values by the first column */
var_dump($sth->fetchAll(PDO::FETCH_COLUMN|PDO::FETCH_GROUP));
?>
Returns:
<?php
array (size=2)
'female' =>
array (size=3)
0 => string '2' (length=1)
1 => string '3' (length=1)
2 => string '4' (length=1)
'male' =>
array (size=2)
0 => string '5' (length=1)
1 => string '6' (length=1)
?>
But,
<?php
var_dump($sth->fetchAll(PDO::FETCH_COLUMN|PDO::FETCH_GROUP, 0));
?>
returns:
<?php
array (size=2)
'female' =>
array (size=3)
0 => string 'female' (length=1)
1 => string 'female' (length=1)
2 => string 'female' (length=1)
'male' =>
array (size=2)
0 => string 'male' (length=1)
1 => string 'male' (length=1)
?>
and
<?php
var_dump($sth->fetchAll(PDO::FETCH_COLUMN|PDO::FETCH_GROUP, 1));
?>
returns
<?php
array (size=5)
2 =>
array (size=1)
0 => string 'female' (length=1)
3 =>
array (size=1)
0 => string 'female' (length=1)
4 =>
array (size=1)
0 => string 'female' (length=1)
5 =>
array (size=1)
0 => string 'male' (length=1)
6 =>
array (size=1)
0 => string 'male' (length=1)
?>
First column is retuned and grouping is done by provided column index.
I was blown away that you can actually combine PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE | PDO::FETCH_UNIQUE, because both PDO::FETCH_CLASSTYPE and PDO::FETCH_UNIQUE say they will use the first column, but it turns out PDO::FETCH_CLASSTYPE goes first and then PDO::FETCH_UNIQUE will use the next column. This way you can create an associative array of objects, with one of the table columns as key. For example a query such as
'SELECT Class, Id, t.* FROM subscriptions_tbl t'
might give you this result:
Array
(
[20481086] => WConsumerSubscription Object
(
[Variant] => 2
[_Expiration:WSubscriptionModel:private] => DateTime Object
(
[date] => 2018-08-08 00:00:00.000000
[timezone_type] => 3
[timezone] => UTC
)
[Notes] =>
[Id] => 20481086
[_Deleted:protected] => 0
[_VersionNo:protected] => 2
[ContactId] =>
[ConsumerId] => 2
)
[21878324] => WAdminSubscription Object
(
[Variant] =>
[_Expiration:WSubscriptionModel:private] =>
[Notes] =>
[Id] => 21878324
[_Deleted:protected] => 0
[_VersionNo:protected] => 1
[ContactId] =>
)
)
Inject the parameters directly into `fetchAll` instead of using `bindValue`
$query = "
SELECT
a.total_paid_tax_incl AS prize,
a.date_add AS date_add
FROM orders a
WHERE a.order_id = :seventeen
AND a.name = :name";
// connection (Example in Symfony you use class Connection in namespace Doctrine\DBAL\Connection)
$this->connection->fetchAll($query, ['seventeen' => 70, 'name' => 'Sidi'])
Method with Return object (PHP 7.2)
class MySql {
public function __construct()
{
parent::__construct();
try{
$options = array
(
PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES UTF8"
);
$this->pdo = new PDO('mysql:host=127.0.0.1;dbname=testuser','dbtest', 'xxxxxxx',$options);
$this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}catch(PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
die();
}
}
public function selectAll(string $sql)
{
$conn = $this->pdo->query($sql);
return $conn->fetchAll(PDO::FETCH_OBJ);
}
}
There is a breaking change upgrading from PHP<7.4 to PHP 8.0. If your class extend PDOStatement, the PHP 8.0 typed prototype is incompatible :
- PHP 7.4 = public PDOStatement::fetchAll ([ int $fetch_style [, mixed $fetch_argument [, array $ctor_args = array() ]]] ) : array
- PHP 8.0 = public PDOStatement::fetchAll ([ int $mode = PDO::FETCH_BOTH[, mixed ...$args] ]) : array
While they are compatible for a human being, PHP is not enjoying it :
- PHP 7.4 = PHP Warning: Declaration of (your class prototype) should be compatible with (PDOStatement's prototype)
- PHP 8.0 = [PhpCompileError] Declaration of (your class prototype) must be comptable with (PDOStatement's prototype)
Because the first one is a warning, it is not fatal, and you might be happy using PHP 8.0's prototype. My personal solution was to stop extending PDOStatement and thus rewrite associated typing declarations and conditions.
I noticed quite a weird (at least for me) behaviour. Maybe it can help someone who will struggle with this too.
<?php
$stmt = new PDOStatement();
$foo = $stmt->fetchAll();
var_dump($foo);
$stmt = $pdo->prepare('SELECT VERSION()');
$foo = $stmt->fetchAll();
var_dump($foo);
$stmt = $pdo->prepare("INSERT INTO `tblnm` (date) VALUES (NOW())");
$stmt->execute();
$foo = $stmt->fetchAll();
var_dump($foo);
$stmt = $pdo->query("INSERT INTO `tblnm` (date) VALUES (NOW())");
$foo = $stmt->fetchAll();
var_dump($foo);
?>
The first is just an empty object, so $foo === bool(false)
The second one is not executed, so $foo === array(0) {}
The third and fourth throw exception at fetchAll():
"General error: 2014 Cannot execute queries while other unbuffered queries are active. Consider using PDOStatement::fetchAll(). Alternatively, [...] you may enable query buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY attribute."
fetchAll() is already used, and changing the above attribute between true and false changes nothing.
This is probably caused by the INSERT not having any return value. We could use RETURNING in the sql, but it's quite new, so may not yet be supported everywhere.
What finally worked for me, was $pdo->exec() and lastInsertId(), because ID is the only column I needed anyway.
<?php
$count = $pdo->exec('INSERT INTO `tblnm` (date) VALUES (NOW())');
$foo = $pdo->lastInsertId();
var_dump($foo);
?>
Then e.g. $foo === string(2) "93"
I am adding this here as I don’t seem to find any clear and easy to find examples and explanations of PDO::FETCH_GROUP and how it works by means of an example.
I find this to be one of the most useful modes available in fetchAll() when you need to work with any form of grouping.
In essence, PDO can group results into nested arrays, based on the first field selected.
Example
<?php
$data = $pdo->query('SELECT sex, name, car FROM users')->fetchAll(PDO::FETCH_GROUP);
/* array (
'male' => array ( 0 =>
array (
'name' => 'John',
'car' => 'Toyota',
),
1 => array (
'name' => 'Mike',
'car' => 'Ford',
),
),
'female' => array (
0 => array (
'name' => 'Mary',
'car' => 'Mazda',
),
1 => array (
'name' => 'Kathy',
'car' => 'Mazda',
),
),
) */
?>
Tip: If you need to group the data by something other than the first field then you can do it like this as well
<?php
SELECT sex, users.* FROM users
?>
Note that \PDO::FETCH_DEFAULT was not introduced until PHP 8.0.7 and 8.1.0. It will throw an undefined constant error in earlier versions.