SQLite3::createAggregate
(PHP 5 >= 5.3.0)
SQLite3::createAggregate — Registers a PHP function for use as an SQL aggregate function
Описание
$name
, mixed $step_callback
, mixed $final_callback
[, int $argument_count = -1
] )Registers a PHP function or user-defined function for use as an SQL aggregate function for use within SQL statements.
Список параметров
-
name -
Name of the SQL aggregate to be created or redefined.
-
step_callback -
The name of a PHP function or user-defined function to apply as a callback for every item in the aggregate.
-
final_callback -
The name of a PHP function or user-defined function to apply as a callback at the end of the aggregate data.
-
argument_count -
The number of arguments that the SQL aggregate takes. If this parameter is negative, then the SQL aggregate may take any number of arguments.
Возвращаемые значения
Returns TRUE upon successful creation of the aggregate, FALSE on
failure.
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения для работы с базами данных
- Расширения для работы с базами данных отдельных производителей
- SQLite3
- Функция SQLite3::busyTimeout() - Sets the busy connection handler
- SQLite3::changes
- Функция SQLite3::close() - Closes the database connection
- Функция SQLite3::__construct() - Instantiates an SQLite3 object and opens an SQLite 3 database
- Функция SQLite3::createAggregate() - Registers a PHP function for use as an SQL aggregate function
- Функция SQLite3::createCollation() - Registers a PHP function for use as an SQL collating function
- Функция SQLite3::createFunction() - Registers a PHP function for use as an SQL scalar function
- SQLite3::enableExceptions
- Функция SQLite3::escapeString() - Returns a string that has been properly escaped
- Функция SQLite3::exec() - Executes a result-less query against a given database
- Функция SQLite3::lastErrorCode() - Returns the numeric result code of the most recent failed SQLite request
- Функция SQLite3::lastErrorMsg() - Returns English text describing the most recent failed SQLite request
- Функция SQLite3::lastInsertRowID() - Returns the row ID of the most recent INSERT into the database
- Функция SQLite3::loadExtension() - Attempts to load an SQLite extension library
- Функция SQLite3::open() - Opens an SQLite database
- SQLite3::openBlob
- Функция SQLite3::prepare() - Подготавливает SQL-запрос для выполнения
- Функция SQLite3::query() - Выполняет SQL-запрос
- Функция SQLite3::querySingle() - Executes a query and returns a single result
- Функция SQLite3::version() - Returns the SQLite3 library version as a string constant and as a number
Коментарии
Lacks of example, right?
Let's try to give to SQlite3 the capability like ones of MySQL's
- REGEXP operator,
- MD5 function, and
- GROUP_CONCAT aggregate function
$db = new SQLite3($filename);
$db->createFunction('regexp', function ($a,$b) { return preg_match("/$a/i", $b); });
$db->createFunction('md5', function ($a) { return md5($a); });
$db->createAggregate ('group_concat',
function(&$context, $rownumber, $str) { $context[]=$str; return $context; },
function(&$context) {return implode(",", (array) $context); });
<?phpclass Test extends SQLite3
{
public function __construct($file)
{
parent::__construct($file);
$this->createAggregate('groupConcat', [$this, 'concatStep'], [$this, 'concatFinal']);
}
public function concatStep(&$context, $rowId, $string, $delimiter)
{
if (!isset($context)) {
$context = [
'delimiter' => $delimiter,
'data' => []
];
}
$context['data'][] = $string;
return $context;
}
public function concatFinal(&$context)
{
return implode($context['delimiter'], $context['data']);
}
}
$SQLite = new Test('/tmp/test.sqlite');
$SQLite->exec("create table `test` (`id` TEXT, `color` TEXT, `size` TEXT)");
$SQLite->exec("insert into `test` (`id`, `color`, `size`) values ('1', 'red', 'M')");
$SQLite->exec("insert into `test` (`id`, `color`, `size`) values ('1', 'green', 'M')");
$SQLite->exec("insert into `test` (`id`, `color`, `size`) values ('1', 'blue', 'S')");
$Result = $SQLite->query("select `size`, groupConcat(`color`, ';') as `color` from `test` group by `size`");
while ($row = $Result->fetchArray(SQLITE3_ASSOC)) {
print_r($row);
}
/*
Array
(
[size] => M
[color] => red;green
)
Array
(
[size] => S
[color] => blue
)
*/