PHP Manual
MysqlndUhConnection
Returns the number of columns for the most recent query

MysqlndUhConnection::getFieldCount

(PECL mysqlnd-uh >= 1.0.0-alpha)

MysqlndUhConnection::getFieldCount — Returns the number of columns for the most recent query

说明

public MysqlndUhConnection::getFieldCount ( mysqlnd_connection $connection ) : int

Returns the number of columns for the most recent query.

参数

connection: Mysqlnd connection handle. Do not modify!

返回值

Number of columns.

范例

MysqlndUhConnection::getFieldCount() is not only executed after the invocation of a user space API call which maps directly to it but also called internally.

Example #1 MysqlndUhConnection::getFieldCount() example

 <?php
class proxy extends MysqlndUhConnection {
 public function getFieldCount($res) {
   printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
   $ret = parent::getFieldCount($res);
   printf("%s returns %s\n", __METHOD__, var_export($ret, true));
   return $ret;
 }
}
mysqlnd_uh_set_connection_proxy(new proxy());

$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->query("WILL_I_EVER_LEARN_SQL?");
var_dump($mysqli->field_count);
$mysqli->query("SELECT 1, 2, 3 FROM DUAL");
var_dump($mysqli->field_count);
?>

以上例程会输出：

proxy::getFieldCount(array (
  0 => NULL,
))
proxy::getFieldCount returns 0
int(0)
proxy::getFieldCount(array (
  0 => NULL,
))
proxy::getFieldCount returns 3
proxy::getFieldCount(array (
  0 => NULL,
))
proxy::getFieldCount returns 3
int(3)

参见

mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
mysqli_field_count() - Returns the number of columns for the most recent query