mysqli_result::data_seek

mysqli_data_seek

(PHP 5, PHP 7, PHP 8)

mysqli_result::data_seek -- mysqli_data_seek — Adjusts the result pointer to an arbitrary row in the result

说明

面向对象风格

public mysqli_result::data_seek(int $offset): bool

过程化风格

mysqli_data_seek(mysqli_result $result, int $offset): bool

The mysqli_data_seek() function seeks to an arbitrary result pointer specified by the offset in the result set.

参数

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。
offset: The row offset. Must be between zero and the total number of rows minus one (0..mysqli_num_rows() - 1).

返回值

成功时返回 true，或者在失败时返回 false。

示例

示例 #1 mysqli::data_seek() example

面向对象风格

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$query = "SELECT Name, CountryCode FROM City ORDER BY Name";
$result = $mysqli->query($query);

/* Seek to row no. 401 */
$result->data_seek(400);

/* Fetch single row */
$row = $result->fetch_row();

printf("City: %s  Countrycode: %s\n", $row[0], $row[1]);

过程化风格

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

$query = "SELECT Name, CountryCode FROM City ORDER BY Name";

$result = mysqli_query($link, $query);

/* Seek to row no. 401 */
mysqli_data_seek($result, 400);

/* Fetch single row */
$row = mysqli_fetch_row($result);

printf ("City: %s  Countrycode: %s\n", $row[0], $row[1]);

以上示例会输出：

City: Benin City  Countrycode: NGA

示例 #2 Adjusting the result pointer when iterating

This function can be useful when iterating over the result set to impose a custom order or rewind the result set when iterating multiple times.

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$query = "SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 15,4";
$result = $mysqli->query($query);

/* Iterate the result set in reverse order */
for ($row_no = $result->num_rows - 1; $row_no >= 0; $row_no--) {
    $result->data_seek($row_no);

    /* Fetch single row */
    $row = $result->fetch_row();

    printf("City: %s  Countrycode: %s\n", $row[0], $row[1]);
}

/* Reset pointer to the beginning of the result set */
$result->data_seek(0);

print "\n";

/* Iterate the same result set again */
while ($row = $result->fetch_row()) {
    printf("City: %s  Countrycode: %s\n", $row[0], $row[1]);
}

以上示例会输出：

City: Acmbaro  Countrycode: MEX
City: Abuja  Countrycode: NGA
City: Abu Dhabi  Countrycode: ARE
City: Abottabad  Countrycode: PAK

City: Abottabad  Countrycode: PAK
City: Abu Dhabi  Countrycode: ARE
City: Abuja  Countrycode: NGA
City: Acmbaro  Countrycode: MEX

注释

注意:
This function can only be used with buffered results attained from the use of the mysqli_store_result(), mysqli_query() or mysqli_stmt_get_result() functions.

参见

mysqli_store_result() - 传输上次查询的结果集
mysqli_fetch_row() - Fetch the next row of a result set as an enumerated array
mysqli_fetch_array() - Fetch the next row of a result set as an associative, a numeric array, or both
mysqli_fetch_assoc() - Fetch the next row of a result set as an associative array
mysqli_fetch_object() - Fetch the next row of a result set as an object
mysqli_query() - 对数据库执行查询
mysqli_num_rows() - Gets the number of rows in the result set