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    mysql_data_seek

    (PHP 4, PHP 5)

    mysql_data_seek — Move internal result pointer

    Avviso

    Questa enstensione deprecata da PHP 5.5.0, e sarà rimossa in futuro. Al suo posto, usare l'estensione MySQLi o PDO_MySQL. Vedere anche la guida MySQL: scelta dell'API e le FAQ relative per ulteriori informazioni. Le alternative a questa funzione includono:

    Descrizione

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

    mysql_data_seek() moves the internal row pointer of the MySQL result associated with the specified result identifier to point to the specified row number. The next call to a MySQL fetch function, such as mysql_fetch_assoc(), would return that row.

    row_number starts at 0. The row_number should be a value in the range from 0 to mysql_num_rows() - 1. However if the result set is empty (mysql_num_rows() == 0), a seek to 0 will fail with an E_WARNING and mysql_data_seek() will return false.

    Elenco dei parametri

    result

    The risultato resource che che viene calcolato. Questo risultato deriva dal una chiamata a mysql_query().

    row_number

    The desired row number of the new result pointer.

    Valori restituiti

    Restituisce true in caso di successo, false in caso di fallimento.

    Esempi

    Example #1 mysql_data_seek() example

    <?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);
    ?>

    Note

    Nota:

    The function mysql_data_seek() can be used in conjunction only with mysql_query(), not with mysql_unbuffered_query().

    Vedere anche:

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    User Contributed Notes 4 notes

    up
    6
    kennethnash1134 at yahoo dot com
    20 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
    arturo_b at hotmail dot com
    19 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
    saeed at photobookworldwide dot com
    12 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
    b.steinbrink at g m x dot de
    19 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
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