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SQL: Top 3 Products Each Month
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SQL: Top 3 Products Each Month

MediumSQL · PostgreSQL

Problem

Write an SQL query to find the top 3 products by sales in each month.

Use the provided product and sales data. Sales are calculated as quantity multiplied by unit price. Return exactly three products per month when at least three products have sales.

Output

  1. One row per qualifying product and month
  2. Columns: sales_month, product_id, product_name, total_sales, and sales_rank
  3. Sort by month ascending, rank ascending, and product name ascending for deterministic tie-breaking

Output details

  • Represent each sales_month as the first calendar day of its month.
  • Exclude sales rows whose sale_date is NULL.
  • Exclude sales lacking a matching product record.
  • Rank products by total_sales descending, breaking ties by product_name ascending.
  • Return the computed total_sales without additional rounding.

Schema

products
ColumnTypeDescription
product_idPKINTUnique product identifier
product_nameVARCHAR(100)Product display name
sales
ColumnTypeDescription
sale_idPKINTUnique sale identifier
product_idINTProduct associated with the sale
sale_dateDATEDate on which the sale occurred
quantityINTNumber of units sold
unit_priceDECIMAL(10,2)Price per unit at the time of sale
Tablesproductssales
Interviewer

Whenever you're ready, walk me through your approach or go straight to the code. The requirements and the two tables are in the Question tab.

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