mysql_num_fields

(PHP 4, PHP 5, PECL mysql:1.0)

mysql_num_fields — Retourne le nombre de champs d'un résultat MySQL

Description

int mysql_num_fields ( resource $result )

Retourne le nombre de champs d'une requête.

Liste de paramètres

result: La ressource de résultat qui vient d'être évaluée. Ce résultat vient de l'appel à la fonction mysql_query().

Valeurs de retour

Retourne le nombre de champs d'un jeu de résultat en cas de succès, ou FALSE si une erreur survient.

Exemples

Exemple #1 Exemple avec mysql_num_fields()


<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
   echo 'Impossible d\'exécuter la requête : ' . mysql_error();
   exit;
}

/* Retourne 2 car id,email === 2 champs */
echo mysql_num_fields($result);
?>

Notes

Note: Pour des raisons de compatibilité ascendante, l'alias obsolète suivant peut être utilisé : mysql_numfields()

Voir aussi

mysql_num_rows

mysql_list_tables

Last updated: Fri, 20 Jun 2008

add a note User Contributed Notes
mysql_num_fields

php at jezusisheer dot nl
30-Mar-2007 12:10


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.

tharkey at tharkey dot net
19-Jun-2003 11:26


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 (' / ');

                        }

apass AT passmoore DOT com
01-Oct-2002 03:52


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.

matt at iwdt dot net
23-Sep-2001 06:09


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

bwark at stanford dot edu
24-Dec-2000 02:56


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.

add a note

mysql_num_rows

mysql_list_tables

Last updated: Fri, 20 Jun 2008