MySQLi_Result
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mysqli_result::$num_rows

mysqli_num_rows

(PHP 5)

mysqli_result::$num_rows -- mysqli_num_rows — Gets the number of rows in a result

说明

面向对象风格

int $mysqli_result->num_rows;

过程化风格

int mysqli_num_rows ( mysqli_result $result )

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.

参数

result

仅以过程化样式：由 mysqli_query()，mysqli_store_result() 或 mysqli_use_result() 返回的结果集标识。

返回值

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.

范例

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.

参见

MySQLi_Result
在线手册：中文 英文
PHP手册
PHP手册 - N: Gets the number of rows in a result

用户评论:

jonteh at zaphotel dot net (22-Mar-2012 08:00)

<?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 (08-Aug-2011 04:19)

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
?>

randomsort at gmail dot com (27-Jun-2011 09:39)

This may be a bug or a feature, but I do see peculiar behaviour with regards to this feature on  php version  5.2.6-1+lenny10.

The value in mysqli-result->num_rows is not the total number of rows, but rather the number of rows you have iterated over so far.

<?php
$sql = "valid select statement that yields results";
if($result = mysqli-connection->query($sql, MYSQLI_USE_RESULT))
{
          echo $result->num_rows; //zero
          while($row = $result->fetch_row())
        {
          echo $result->num_rows; //incrementing by one each time
        }
          echo $result->num_rows; // Finally the total count
}
?>

This has had me confused more than a few times,
I hope I can save you some of that trouble.

Regards,
Johan Abildskov