PHP 8.3.0 RC 6 available for testing
    Submit a Pull Request Report a Bug

    mysql_data_seek

    (PHP 4, PHP 5)

    mysql_data_seek — 移动内部结果的指针

    警告

    本扩展自 PHP 5.5.0 起已废弃，并在自 PHP 7.0.0 开始被移除。应使用 MySQLi 或 PDO_MySQL 扩展来替换之。参见 MySQL：选择 API 指南来获取更多信息。用以替代本函数的有：

    说明

    mysql_data_seek(resource $result, int $row_number): bool

    mysql_data_seek() 将指定的结果标识所关联的 MySQL 结果内部的行指针移动到指定的行号。接着调用 mysql_fetch_row() 将返回那一行。

    row_number 从 0 开始。row_number 的取值范围应该从 0 到 mysql_num_rows - 1。但是如果结果集为空（mysql_num_rows() == 0），要将指针移动到 0 会失败并发出 E_WARNING 级的错误，mysql_data_seek() 将返回 false。

    参数

    result

    resource 型的结果集。此结果集来自对 mysql_query() 的调用。

    row_number

    想要设定的新的结果集指针的行数。

    返回值

    成功时返回 true， 或者在失败时返回 false。

    示例

    示例 #1 mysql_data_seek() 示例

    <?php
    $link     = mysql_connect('localhost', 'mysql_user', 'mysql_password');
    if (!    $link) {
    die(    'Could not connect: ' . mysql_error());
    }
    $db_selected = mysql_select_db('sample_db');
    if (!    $db_selected) {
    die(    'Could not select database: ' . mysql_error());
    }
    $query = 'SELECT last_name, first_name FROM friends';
    $result = mysql_query($query);
    if (!    $result) {
    die(    'Query failed: ' . mysql_error());
    }
    /* fetch rows in reverse order */
    for ($i = mysql_num_rows($result) - 1; $i >= 0; $i--) {
    if (!    mysql_data_seek($result, $i)) {
    echo     "Cannot seek to row $i: " . mysql_error() . "\n";
    continue;
    }

    if (!(    $row = mysql_fetch_assoc($result))) {
    continue;
    }

    echo     $row['last_name'] . ' ' . $row['first_name'] . "<br />\n";
    }

    mysql_free_result($result);
    ?>

    注释

    注意:

    mysql_data_seek() 只能和 mysql_query() 结合起来使用，而不能用于 mysql_unbuffered_query()。

    参见

    ＋add a note

    User Contributed Notes 6 notes

    up
    6
    kennethnash1134 at yahoo dot com
    19 years ago
    /*here is a nice function for converting a mysql result row set into a 2d array, a time saver if need small data from several rows, saves you from having to do Alot of queries... would be nice to have this built into PHP future versions :) */

    // simple example query
    $r=mysql_query("select user,id,ip from accounts limit 10");

    //starts the for loop, using mysql_num_rows() to count total
    //amount of rows returned by $r
    for($i=0; $i<mysql_num_rows($r); $i++){
    //advances the row in the mysql resource $r
    mysql_data_seek($r,$i);
    //assigns the array keys, $users[row][field]
    $users[$i]=mysql_fetch_row($r);
    }

    //simple, hope someone can use it :)
    // -Kenneth Nash
    up
    2
    saeed at photobookworldwide dot com
    11 years ago
    Here, you can find the current pointer of selected row easily:

    <?php
    //selected row with id=4
    $id = "4";

    $result = mysql_query("select * from jos_components");

    $num = mysql_num_rows($result);

    for(    $i=0;$i<$num;$i++){

    mysql_data_seek($result,$i);

    $row = mysql_fetch_assoc($result);

    if(    $row['id'] == $id){

    $pointer = $i;
    }


    }

    // current pointer for selected row
    echo $pointer;
    ?>
    up
    2
    arturo_b at hotmail dot com
    18 years ago
    hello, this script would be easy to understand for those that are novice in php whose want to understand about this function:

    the table "user" have 2 columns "id" and "name".
    "user" content:
    position 0: "id"=195342481 "name"='Arthur'
    position 1: "id"=179154675 "name"='John'
    >>position 2<<: "id"=157761949 "name"='April' >>third row<<
    position 3: "id"=124492684 "name"='Tammy'
    position 4: "id"=191346457 "name"='Mike'

    <?php
    mysql_connect    ("localhost", "root")
    mysql_select_db("test");
    $sql = mysql_query("select * from user");
    mysql_data_seek($sql, 2);
    echo     "<table border=1>";
    while (    $row = mysql_fetch_row($sql)){
    echo     "<tr><td>$row[0]</td><td>$row[1]</td></tr>";
    }
    echo     "</tabla>";
    ?>

    explanation:
    mysql_data_seek move internal result pointer to the third row of table user. Thus mysql_fetch_row will begin by april?s row.
    up
    -1
    b.steinbrink at g m x dot de
    18 years ago
    to kennethnash1134 at yahoo dot com

    your loop can be done like this as well and i guess this is faster:

    $r=mysql_query("select user,id,ip from accounts limit 10");

    unset($users); // Just to be sure
    while($users[] = mysql_fetch_row);
    array_pop($users); // Drop the last entry which is FALSE
    up
    -5
    Daniel
    15 years ago
    Here is a simple function to "peek" at the position of the internal pointer in a query result:

    <?php
    function mysql_pointer_position($result_set) {
    $num_rows = mysql_num_rows($result_set);
    $i = 0;
    while(    $result = mysql_fetch_array($result_set)) {
    $i++;
    }
    $pointer_position = $num_rows - $i;

    //Return pointer to original position
    if($pointer_position <= $num_rows - 1) {
    mysql_data_seek($result_set, $pointer_position);
    }
    return     $pointer_position;
    }
    ?>
    up
    -6
    Anonymous
    17 years ago
    A helpful note about the 'resource' data type.

    Since the 'resource' variable is pointing to a row in a result set at any given time, you can think of it as being passed to this function by reference every time you pass it or assign it to a variable.

    <?

    $sql = "SELECT * from <table>";
    $result = mysql_query($sql);
    $temp_result = $result;

    while ($row = mysql_fetch_assoc($temp_result)) {
    // do stuff with $row
    }

    while ($row = mysql_fetch_assoc($result)) {
    // This code will never run because the 'resource' variable is pointing past the end of the result set,
    // even though it was *not* assigned by reference to $result2.
    }

    ?>

    Therefore, the following snipits are functionally identical:

    <?

    // Start snipit 1

    $sql = "SELECT * from <table>";
    $result = mysql_query($sql);

    while ($row = mysql_fetch_assoc($result)) {
    // do stuff with $row
    }

    mysql_data_seek($result, 0);

    while ($row = mysql_fetch_assoc($result)) {
    // do other stuff with $row
    }

    // Start snipit 2

    $sql = "SELECT * from <table>";
    $result = mysql_query($sql);
    $temp_result = $result;

    while ($row = mysql_fetch_assoc($temp_result)) {
    // do stuff with $row
    }

    mysql_data_seek($result, 0);

    while ($row = mysql_fetch_assoc($temp_result)) {
    // do other stuff with $row
    }

    ?>
    ＋add a note
    To Top