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    mysql_num_fields

    (PHP 4, PHP 5)

    mysql_num_fields — Get number of fields in result

    Warning

    This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide. Alternatives to this function include:

    Description

    mysql_num_fields(resource $result): int|false

    Retrieves the number of fields from a query.

    Parameters

    result

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

    Return Values

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

    Examples

    Example #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);
    ?>

    Notes

    Note:

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

    See Also

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    User Contributed Notes 3 notes

    up
    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
    -2
    matt at iwdt dot net
    23 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
    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.
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