Write a SQL query to find the top three pharmaceutical products by sales volume for each distribution center at McKesson.
Use the provided distribution center, product, and sales data. Sales volume is the total units sold for each product within each center.
center_name, product_name, total_units_sold, and product_rank.| Column | Type | Description |
|---|---|---|
| center_idPK | INT | Unique distribution center identifier |
| center_name | VARCHAR(100) | Distribution center name |
| Column | Type | Description |
|---|---|---|
| product_idPK | INT | Unique pharmaceutical product identifier |
| product_name | VARCHAR(150) | Pharmaceutical product name |
| Column | Type | Description |
|---|---|---|
| sale_idPK | INT | Unique sales record identifier |
| center_id | INT | Distribution center associated with the sale |
| product_id | INT | Product associated with the sale |
| units_sold | INT | Number of product units sold |