Реализовать ROLLUP вручную
Поскольку Redshift в настоящее время не распознает предложение ROLLUP, вы должны усложнить реализацию этой техники группировки.
ОБЪЕДИНЕНИЕ с 1 аргументом
С ROLLUP Ex. PostgreSQL
SELECT column1, aggregate_function(*)
FROM some_table
GROUP BY ROLLUP(column1)
Эквивалентная реализация
-- First, the same GROUP BY without the ROLLUP
-- For efficiency, we will reuse this table
DROP TABLE IF EXISTS tmp_totals;
CREATE TEMP TABLE tmp_totals AS
SELECT column1, aggregate_function(*) AS total1
FROM some_table
GROUP BY column1;
-- Show the table 'tmp_totals'
SELECT * FROM tmp_totals
UNION ALL
-- The aggregation of 'tmp_totals'
SELECT null, aggregate_function(total1) FROM tmp_totals
ORDER BY 1
Пример вывода
Country | Sales
-------- | -----
Poland | 2
Portugal | 4
Ukraine | 3
null | 9
ROLLUP с 2 аргументами
С ROLLUP Ex. PostgreSQL
SELECT column1, column2, aggregate_function(*)
FROM some_table
GROUP BY ROLLUP(column1, column2);
Эквивалентная реализация
-- First, the same GROUP BY without the ROLLUP
-- For efficiency, we will reuse this table
DROP TABLE IF EXISTS tmp_totals;
CREATE TEMP TABLE tmp_totals AS
SELECT column1, column2, aggregate_function(*) AS total1
FROM some_table
GROUP BY column1, column2;
-- Show the table 'tmp_totals'
SELECT * FROM tmp_totals
UNION ALL
-- The sub-totals of the first category
SELECT column1, null, sum(total1) FROM tmp_totals GROUP BY column1
UNION ALL
-- The full aggregation of 'tmp_totals'
SELECT null, null, sum(total1) FROM tmp_totals
ORDER BY 1, 2;
Пример вывода
Country | Segment | Sales
-------- | -------- | -----
Poland | Premium | 0
Poland | Base | 2
Poland | null | 2 <- sub total
Portugal | Premium | 1
Portugal | Base | 3
Portugal | null | 4 <- sub total
Ukraine | Premium | 1
Ukraine | Base | 2
Ukraine | null | 3 <- sub total
null | null | 9 <- grand total
person
ePi272314
schedule
05.07.2019