# LeetCode 1068: Product Sales Analysis I

## Problem Restatement

We have two tables:

`Sales(sale_id, product_id, year, quantity, price)` — each row is a sale.

`Product(product_id, product_name)` — product information.

We need to return `product_name`, `year`, and `price` for each sale.

## Input and Output

| Table | Schema |
|---|---|
| `Sales` | `sale_id INT`, `product_id INT`, `year INT`, `quantity INT`, `price INT` |
| `Product` | `product_id INT`, `product_name VARCHAR` |

Return a table with `product_name`, `year`, `price`.

## Examples

```
Sales:                           Product:
+---------+------------+------+  +------------+--------------+
| sale_id | product_id | year |  | product_id | product_name |
+---------+------------+------+  +------------+--------------+
| 1       | 100        | 2008 |  | 100        | Nokia        |
| 2       | 100        | 2009 |  | 200        | Apple        |
| 7       | 200        | 2011 |  | 300        | Samsung      |
+---------+------------+------+  +------------+--------------+
```

Answer:

```
+--------------+------+-------+
| product_name | year | price |
+--------------+------+-------+
| Nokia        | 2008 | ...   |
| Nokia        | 2009 | ...   |
| Apple        | 2011 | ...   |
+--------------+------+-------+
```

## Edge Cases

- Match the aggregate to the question: use raw `COUNT` or `SUM` for rows/amounts, and `COUNT(DISTINCT ...)` only for unique entities.
- Tie cases should return every qualifying row unless the statement asks for a single row.
- For outer joins, keep filters on the joined table in the `ON` clause when unmatched rows must remain visible.

## Common Pitfalls

- Do not put aggregate filters in `WHERE`; use `HAVING` after `GROUP BY`.
- When the answer needs all tied winners, avoid `LIMIT 1` unless the statement explicitly asks for one row.

## Implementation

```sql
SELECT p.product_name, s.year, s.price
FROM Sales s
JOIN Product p ON s.product_id = p.product_id;
```

## Code Explanation

Join `Sales` with `Product` on `product_id` to get the product name for each sale.

Select `product_name`, `year`, and `price` from the joined result.