Histogram of daily sales in SQL
Question
Suppose you’re given the following tables, showing sales across a 10-day period:
Table: item_sales
| day | num_sales |
|---|---|
| 1 | 1055 |
| 2 | 500 |
| 3 | 300 |
| 4 | 1400 |
| 5 | 900 |
| 6 | 1000 |
| 7 | 1100 |
| 8 | 800 |
| 9 | 1350 |
| 10 | 1000 |
Using this table, write a SQL query to count the number of days where sales fall into bands of 200 (e.g. a histogram). Given the snippet of data in this example, your query should return the following:
| bucket | count |
|---|---|
| 1000-1200 | 4 |
| 800-1000 | 2 |
| 1200-1400 | 1 |
| 1400-1600 | 1 |
| 200-400 | 1 |
| 400-600 | 1 |
Click here to view/query the tables in an interactive SQL fiddle.