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
$offset): bool过程化风格
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 field 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。
范例
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]);
以上例程会输出：
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]);
}
以上例程会输出：
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() - 转移上一次查询返回的结果集
- 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() - 对数据库执行一次查询
- mysqli_num_rows() - Gets the number of rows in the result set
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