Question

I have the following query

$query2 = "SELECT reverse_products.id, reverse_products.name, reverse_relations.user_id
FROM reverse_products JOIN reverse_relations ON reverse_products.id = reverse_relations.product_id
WHERE product_id = $dealid ";

$row = mysql_fetch_array(mysql_query($query2));

echo "$row[id]: $row[name]";

that shows the id and name of a product from reverse_products table. On the reverse_relations table there are stored *user_id* and *product_id*. There are many *user_id* that may have the same *product_id*.

How to change my query to show :
On how many *user_id* have the same *product_id* ? Do I need a second query for this ?

Answer 1

SELECT count(user_id)
FROM reverse_relations
GROUP BY product_id
WHERE product_id = $dealid

if I’m understanding your table structure properly.