(PHP 5)
mysqli_result::$num_rows -- mysqli_num_rows — Gets the number of rows in a result
面向对象风格
过程化风格
Returns the number of rows in the result set.
The behaviour of mysqli_num_rows() depends on whether buffered or unbuffered result sets are being used. For unbuffered result sets, mysqli_num_rows() will not return the correct number of rows until all the rows in the result have been retrieved.
Returns number of rows in the result set.
Note:
If the number of rows is greater than
MAXINT, the number will be returned as a string.
Example #1 面向对象风格
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($result = $mysqli->query("SELECT Code, Name FROM Country ORDER BY Name")) {
/* determine number of rows result set */
$row_cnt = $result->num_rows;
printf("Result set has %d rows.\n", $row_cnt);
/* close result set */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 过程化风格
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($result = mysqli_query($link, "SELECT Code, Name FROM Country ORDER BY Name")) {
/* determine number of rows result set */
$row_cnt = mysqli_num_rows($result);
printf("Result set has %d rows.\n", $row_cnt);
/* close result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
以上例程会输出：
Result set has 239 rows.
jonteh at zaphotel dot net (2012-03-22 00:00:06)
<?php
class mysqlisimple extends mysqli {
public function __construct($hostname, $username, $password, $database) {
$this->connection = @parent::__construct($hostname, $username, $password, $database);
if($this->connection->connect_error) {
die($this->connection->connect_error);
}
}
public function DBResult($query) {
$this->PrepareQuery = $query;
if ($this->Result = $this->query($this->PrepareQuery)) {
while ($this->row = $this->Result->fetch_row()) {
$this->output = $this->row[0];
}
}
return $this->output;
}
}
?>
This is a simple class to extend MySQLi and includes a function to fetch a single result. Was just playing, thought it may help some.
borisigna (2011-08-07 20:19:20)
If you have problems making work this num_rows, you have to declare ->store_result() first.
<?php
$mysqli = new mysqli("localhost","root", "", "tables");
$query = $mysqli->prepare("SELECT * FROM table1");
$query->execute();
$query->store_result();
$rows = $query->num_rows;
echo $rows;
// Return 4 for example
?>