LEAD: Detect Days Where Sales Will Increase Next Day

SQL coding challenge · Difficulty: easy · +50 XP

Problem

The automated buying system should pre-order stock on any day where tomorrow's sales are expected to be HIGHER than today's. Find those days.

Tables

Table: daily_sales

| sale_id | day_name | amount |
| 1 | Mon | 100 |
| 2 | Tue | 200 |
| 3 | Wed | 300 |
| 4 | Thu | 400 |
| 5 | Fri | 500 |

Expected Output

| sale_id | day_name | amount | next_day_sales |
| 1 | Mon | 100 | 200 |
| 2 | Tue | 200 | 300 |
| 3 | Wed | 300 | 400 |
| 4 | Thu | 400 | 500 |

• Return: sale_id, day_name, amount, next_day_sales
• Only rows where next_day_sales > amount
• Exclude the last row (NULL next-day data)
• Hint: Compute LEAD() in a subquery first, then filter