How do I select two max values for two categories for each year in a year range?

  • 11 months ago
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To select two maximum values for two categories for each year in a year range, you can use SQL queries to retrieve the data from a database. Assuming you have a table with columns like year, category, and value, you can use the following approach:

Let's say you have a table named data with the following structure:

yaml
| year | category | value |
|------|----------|-------|
| 2018 | A | 100 |
| 2018 | B | 150 |
| 2018 | C | 200 |
| 2019 | A | 110 |
| 2019 | B | 140 |
| 2019 | C | 180 |
| ... | ... | ... |

You can retrieve the two maximum values for each category in each year range using a SQL query like this (assuming you are using MySQL syntax):

sql
SELECT year, category, value
FROM (
SELECT year, category, value,
ROW_NUMBER() OVER(PARTITION BY year, category ORDER BY value DESC) AS rank
FROM data
) AS ranked_data
WHERE rank <= 2
ORDER BY year, category, value DESC;

This query uses the ROW_NUMBER() window function to assign a rank to each row within each year and category partition based on the descending order of values. It then selects only the rows where the rank is less than or equal to 2.

Replace the table name (data), column names (year, category, value), and any other syntax specific to your database system.

Please note that the above query is just an example and may need to be adapted to your specific database system and data structure.