(PHP 5, PHP 7, PHP 8)
mysqli_result::$num_rows -- mysqli_num_rows — Gets the number of rows in the result set
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.
This function returns 0 for unbuffered result sets unless
all rows have been fetched from the server.
result仅以过程化样式：由 mysqli_query()、mysqli_store_result()、 mysqli_use_result()、mysqli_stmt_get_result() 返回的 mysqli_result 对象。
An int representing the number of fetched rows.
Returns 0 in unbuffered mode unless all rows have been
fetched from the server.
注意:
If the number of rows is greater than
PHP_INT_MAX, the number will be returned as a string.
示例 #1 面向对象风格
<?php
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
$result = $mysqli->query("SELECT Code, Name FROM Country ORDER BY Name");
/* Get the number of rows in the result set */
$row_cnt = $result->num_rows;
printf("Result set has %d rows.\n", $row_cnt);
示例 #2 过程化风格
<?php
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
$result = mysqli_query($link, "SELECT Code, Name FROM Country ORDER BY Name");
/* Get the number of rows in the result set */
$row_cnt = mysqli_num_rows($result);
printf("Result set has %d rows.\n", $row_cnt);
以上例程会输出：
Result set has 239 rows.
注意:
In contrast to the mysqli_stmt_num_rows() function, this function doesn't have object-oriented method variant. In the object-oriented style, use the getter property.