mysql_num_fields
(PHP 4, PHP 5, PECL mysql:1.0)
mysql_num_fields — Возвращает количество полей результата запроса
Описание
int mysql_num_fields
( resource $result
)
mysql_num_fields() возвращает количество полей результата запрооса result .
См. также mysql_select_db(), mysql_query(), mysql_fetch_field() и mysql_num_rows().
Для совместимости, как алиас, доступна устаревшая функция mysql_numfields(). Однако, использовать её крайне не рекомендуется.
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Коментарии
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.
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
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.
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 (' / ');
}
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.