N039-E3 Tier 3 · Intermediate · easy ecommerce · Brightlane

Return the ID, name, and price of every product, plus the product's tier number by `price` in descending order

Part of ROW_NUMBER, RANK, DENSE_RANK in SQL

The problem

Brightlane's product leaderboard assigns a tier number to products based on descending price.

Write a query to return the ID, name, and price of every product, plus the product's tier number by price in descending order.

Assumptions:

  • The products table has one row per product with an id, a name, and a price.
  • Tier number 1 goes to the highest-priced product, with tier values increasing as price decreases.
  • Products with the same price receive the same tier number. The next tier number after a tie is always exactly one higher, so tier values have no gaps.

Output:

  • One row per product, with columns id, name, price, and price_tier.
Schema · ecommerce 5 tables
categories
id integer
name text
parent_id? integer
products
id integer
name text
category_id integer
price numeric
stock_qty integer
attributes? jsonb
order_items
id integer
order_id integer
product_id integer
quantity integer
unit_price numeric
customers
id integer
name text
email text
city? text
country text
created_at timestamptz
is_active boolean
orders
id integer
customer_id integer
ordered_at timestamptz
status text
total_amount numeric

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Worked solution Try it yourself first
Solution query
SELECT
  id,
  name,
  price,
  DENSE_RANK() OVER (
    ORDER BY
      price DESC
  ) AS price_tier
FROM
  products

The shape

DENSE_RANK() OVER (ORDER BY price DESC) assigns each distinct price its own consecutive integer and gives every product at that price the same value. Two products tied at the top both get 1, the next-distinct price gets 2, with no gap in between regardless of how many products were tied at 1.

Clause by clause

  • SELECT id, name, price, DENSE_RANK() OVER (ORDER BY price DESC) AS price_tier returns each product's ID, name, price, and a tier number that groups products by price band. The window's ORDER BY price DESC defines the descending price order; without PARTITION BY, every product is in the same window.
  • FROM products reads the product catalog.

Why DENSE_RANK and not RANK

Both functions give tied rows the same number. RANK then skips ahead by the number of tied rows, so 1, 1, 3, .... DENSE_RANK does not skip, so 1, 1, 2, .... When the output is meant to read as "price tier" or "category level," consecutive integers without gaps map cleanly to tier 1, tier 2, tier 3. When the output is meant to be a competitive ranking where the gap communicates how many products sat above, RANK is the right function. The two are interchangeable on tie-free data and divergent the moment a tie appears.

You practiced DENSE_RANK() OVER (ORDER BY ...) — tied rows share the same value; the next value advances by exactly 1, so the sequence is gap-free.

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