More aggregate statistics!
Can we calculate more than one aggregate statistic while grouping? Surely we can!
For example, from the audi_cars table, we can calculate the maximum price and tax for each year.
SELECT AVG(price) AS "avg_price", AVG(tax) AS "avg_tax", year FROM audi_cars GROUP BY year
Please note, while grouping you can put non-aggregated function within
SELECTstatement only if it figures withinGROUP BY, otherwise - it has to be aggregated.
Also note, that in the example above without aliases (
AS) there will be two columns with identical names, which is unacceptable in SQL.
Another note: you can use aggregate functions for ordering after
GROUP BYstatement. It will filter based on calculations within groups.
Swipe to start coding
From the audi_cars table find out the minimum and the maximum prices for each model. Sort in descending order by minimum price.
Ratkaisu
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