Alternative SQL ANSI for TOP WITH TIES - sql

Question

I have two tables:
product
id_product
description
price
id_category
category
id_category
description
I would like to know the categories that have more products. For example, the category food has 10 products and the eletronics too. They are the same.
Now I'm using SQL Server and I'm using TOP WITH TIES.
SELECT TOP 1 WITH TIES p.id_category, COUNT(*) as amount FROM product p
JOIN category c ON p.id_category = c.id_category
GROUP BY p.id_category
ORDER BY amount
Is there another way to solve this with good performance?
I tried also with DENSE_RANK where the position is = 1.
It also works.
SELECT * FROM (
SELECT p.id_category, COUNT(*) as amount, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) position FROM product p
JOIN category c ON p.id_category = c.id_category
GROUP BY p.id_category
) rnk
WHERE rnk.position = 1
But I want this solution in SQL ANSI.
I tried using MAX(COUNT(*)) but it doesn't work.
Is there a general solution? Is This solution better than using TOP WITH TIES?

Answer 1

Here is a third option for SQL Server:
WITH cte AS (
SELECT p.id_category, COUNT(*) AS cnt
FROM product p
INNER JOIN category c
ON p.id_category = c.id_category
GROUP BY p.id_category
)
SELECT *
FROM cte
WHERE cnt = (SELECT MAX(cnt) FROM cte);
If you also cannot rely on CTEs being available, you can easily enough just inline the CTE into the query. From a performance point of view, DENSE_RANK would probably outperform my answer.
With the CTE removed this becomes:
SELECT *
FROM
(
SELECT p.id_category, COUNT(*) AS cnt
FROM product p
INNER JOIN category c
ON p.id_category = c.id_category
GROUP BY p.id_category
)
WHERE cnt = (SELECT MAX(cnt) FROM (
SELECT p.id_category, COUNT(*) AS cnt
FROM product p
INNER JOIN category c
ON p.id_category = c.id_category
GROUP BY p.id_category
));
This query would even run on MySQL. As you can see, the query is ugly, which is one reason why things like CTE and analytic functions were introduced into the ANSI standard.