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    mysql_num_fields

    (PHP 4, PHP 5)

    mysql_num_fields — Get number of fields in result

    Suggested alternatives

    Use of this extension is discouraged. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:

    Beskrivelse

    int mysql_num_fields ( resource $result )

    Retrieves the number of fields from a query.

    Parametre

    result

    The result resource that is being evaluated. This result comes from a call to mysql_query().

    Returnerings Værdier

    Returns the number of fields in the result set resource on success or FALSE on failure.

    Eksempler

    Eksempel #1 A mysql_num_fields() example

    <?php
    $result     = mysql_query("SELECT id,email FROM people WHERE id = '42'");
    if (!    $result) {
        echo     'Could not run query: ' . mysql_error();
        exit;
    }

    /* returns 2 because id,email === two fields */
    echo mysql_num_fields($result);
    ?>

    Noter

    Note:

    For backward compatibility, the following deprecated alias may be used: mysql_numfields()

    Se også

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    User Contributed Notes 5 notes

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    0
    php at jezusisheer dot nl
    17 years ago
    Note that, if you want to get the amount of columns of a table and you're using the "SHOW COLUMNS FROM $table" query, you will have to use mysql_num_rows() instead of mysql_num_fields() on the result. This becomes logical when thinking about it, because the SHOW COLUMNS query returns a result with six columns (Field, Type, Null, Key, Default and Extra) and with a single row for every column found. If you'd count the number of fields, you'd always get 6. If you count the number of rows, you'll get the amount of columns found.
    up
    -3
    matt at iwdt dot net
    22 years ago
    here's one way to print out a row of <th> tags from a table
    NOTE: i didn't test this

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

    for ($i = 0; $i < mysql_num_fields($result); $i++) {
        print "<th>".mysql_field_name($result, $i)."</th>\n";
    }

    post a comment if there's an error
    up
    -5
    tharkey at tharkey dot net
    20 years ago
    You can use it without a requete, just to list the fields :

    $liste_champs = mysql_list_fields ( $Base, $Table, $connexion);

    for ($i=0; $i < mysql_num_fields ($l_champs); $i++) {
                            echo ( mysql_field_name ($l_champs, $i) );
                            echo (' / ');
                            }
    up
    -5
    bwark at stanford dot edu
    23 years ago
    If you just want the number of fields in a table, you can do something like this:

    <?php
    $db_id     = mysql_connet();
    $result = mysql_query("DESCRIBE [tableName], $db_id);

    $numFields = mysql_num_rows($result);
    ?>

    Because "    DESCRIBE" returns one row for each field in the table (at least in MySQL), this will work.
    up
    -11
    apass AT passmoore DOT com
    21 years ago
    Adding to the last comment: you can dynamically loop through any number of  columns AND rows like so-

    $query="your SQL";
    $result=mysql_query($query) or die("Query ($query) sucks!");
    $fields=mysql_num_fields($result);

    echo "<table>\n<tr>";
    for ($i=0; $i < mysql_num_fields($result); $i++) //Table Header
    { print "<th>".mysql_field_name($result, $i)."</th>"; }
    echo "</tr>\n";
    while ($row = mysql_fetch_row($result)) { //Table body
    echo "<tr>";
        for ($f=0; $f < $fields; $f++) {
        echo "<td>$row[$f]</td>"; }
    echo "</tr>\n";}
    echo "</table><p>";

    This has been tested.
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