mysql_list_tables
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.
mysql_num_fields
(PHP 4, PHP 5, PECL mysql:1.0)
mysql_num_fields — Liefert die Anzahl der Felder in einem Ergebnis
Beschreibung
int mysql_num_fields
( resource $Ergebnis-Kennung
)
mysql_num_fields() liefert die Anzahl der Felder in der Ergebnismenge, die mit dem Parameter Ergebnis-Kennung angegeben wurde.
Beispiel #1 Ein mysql_num_fields() Beispiel
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Abfrage konnte nicht ausgeführt werden: ' . mysql_error();
exit;
}
/* Gibt 2 zurück, weil id,email === zwei Felder */
echo mysql_num_fields($result);
?>
Für Abwärtskompatibilität kann mysql_numfields() verwendet werden. Diese Funktion ist jedoch veraltet.
Siehe auch mysql_select_db(), mysql_query(), mysql_fetch_field() und mysql_num_rows().
add a note
User Contributed Notesmysql_num_fields
php at jezusisheer dot nl
30-Mar-2007 12:10
30-Mar-2007 12:10
tharkey at tharkey dot net
19-Jun-2003 11:26
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
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
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
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.