learning-sql/chapter-16.sql at main · Brandel-T/learning-sql · GitHub

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-- chapter 14: analytical functions (windows functions)
use sakila;

SELECT quarter(payment_date) quarter,
	monthname(payment_date) month_nm,
    sum(amount) monthly_sales
FROM payment
WHERE year(payment_date) = 2005
GROUP BY quarter, month_nm;

SELECT QUARTER(payment_date) quarter,
	MONTHNAME(payment_date) month_nm,
    SUM(amount) monthly_sales,
    MAX(SUM(amount))
		OVER () max_overall_sales,
    MAX(SUM(amount))
		OVER (PARTITION BY QUARTER(payment_date)) max_quarter_sales
FROM payment
WHERE year(payment_date) = 2005
GROUP BY QUARTER(payment_date), MONTHNAME(payment_date);

-- rank in the whole result set, which is our `window` in this case
-- (since the OVER clause does not contain a PARTITION BY clause)
SELECT
	QUARTER(payment_date) quarter,
	MONTHNAME(payment_date) month_nm,
    SUM(amount) monthly_sales,
    RANK() OVER(ORDER BY SUM(amount) DESC) sales_rank
FROM payment
WHERE YEAR(payment_date) = 2005
GROUP BY quarter, month_nm
ORDER BY quarter, month_nm;

SELECT
	QUARTER(payment_date) quarter,
    MONTHNAME(payment_date) month_nm,
    SUM(amount) monthly_sales,
    RANK() OVER(
		PARTITION BY QUARTER(payment_date)
        ORDER BY SUM(amount) DESC
	) qtr_sales_rank
FROM payment
WHERE YEAR(payment_date) = 2005
GROUP BY quarter, month_nm
ORDER BY quarter, month_nm;

-- row number
SELECT
	QUARTER(payment_date) quarter,
    MONTHNAME(payment_date) month_nm,
    SUM(amount) monthly_sales,
    ROW_NUMBER() OVER(
		PARTITION BY QUARTER(payment_date)
        ORDER BY SUM(amount) DESC
	) qtr_sales_row_number
FROM payment
WHERE YEAR(payment_date) = 2005
GROUP BY quarter, month_nm
ORDER BY quarter, month_nm;

-- DENSE RANK
SELECT
	QUARTER(payment_date) quarter,
    MONTHNAME(payment_date) month_nm,
    SUM(amount) monthly_sales,
    DENSE_RANK() OVER(
		PARTITION BY QUARTER(payment_date)
        ORDER BY SUM(amount) DESC
	) qtr_sales_dense_rank
FROM payment
WHERE YEAR(payment_date) = 2005
GROUP BY quarter, month_nm
ORDER BY quarter, month_nm;