php mysql help needed

i have some categories of my website i want to show number of inputs in specific category it is smiler when we see a link directory on category name we usually see how many links are in this category or regarding this forum from main we can see how many threads and posts a forum has please help how to do this math
my site is in PHP and database is SQL

regards

 

Adapt to this :

$result = mysql_query("SELECT COUNT(*) AS nr FROM category_table WHERE category_id = NUMBER");
$row = mysql_fetch_array($result);
echo $row['nr'];

PHP:

 

thanks tvoodoo it gives this error

Notice: Undefined index: nr in /usr/home/user/domains/domian.com/public_html/categories.php on line 30

Code (markup):

how ever this worked fine for me

$result = mysql_query("SELECT COUNT(*) FROM category_table WHERE category_id = NUMBER");
$row = mysql_fetch_array($result,MYSQL_BOTH);
echo $row['0'];

Code (markup):

anyway thanks for your great help

 

you should have replaced category_table with your table name and the value NUMBER with a existing category id number !