Transpose Values of Dynamically Created Pivoted Table to Rows - sql

Question

In PostgreSQL I have a table like this:
CREATE TABLE cross_table (brand varchar(10), gender varchar(10), sales int);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Nike', 'Male', 10);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Nike', 'Male', 20);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Adidas', 'Woman', 20);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Nike', 'Male', 10);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Adidas', 'Woman', 30);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Puma', 'Woman', 40);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Puma', 'Male', 10);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Nike', 'Male', 20);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Puma', 'Woman', 10);
INSERT INTO cross_table (brand, gender, sales) VALUES ('Adidas', 'Woman', 20);
Then I can run this query to get brand as rows, gender as columns and "Sum of Sales" and "Count of Sales" as values:
SELECT brand,
jsonb_object_agg(
gender,
json_build_object(
'Sum of Sales', "Sum of Sales",
'Count of Sales', "Count of Sales"
)
) AS gender,
SUM("Sum of Sales") AS "Sum of Sales",
SUM("Count of Sales") AS "Count of Sales"
FROM (
SELECT brand,
gender,
sum(sales) AS "Sum of Sales",
count(sales) AS "Count of Sales"
FROM cross_table
GROUP BY ROLLUP(brand), gender
) AS a
GROUP BY brand
This would produce the following result:
brand
gender
Sum of Sales
Count of Sales
NULL
{"Male": {"Sum of Sales": 70,"Count of Sales": 5},"Woman": {"Sum of Sales": 120, "Count of Sales": 5}}
190
10
adidas
{"Woman": {"Sum of Sales": 70,"Count of Sales": 3}}
70
3
nike
{"Male": {"Sum of Sales": 60, "Count of Sales": 4}}
60
4
puma
{"Male": {"Sum of Sales": 10,"Count of Sales": 1 }, "Woman": {"Sum of Sales": 50,"Count of Sales": 2}}
60
3
But I would like to have the values as rows like this:
brand
values
Male
Woman
Total
null
Sum of Sales
70
120
190
Count of Sales
5
5
10
adidas
Sum of Sales
70
70
Count of Sales
3
3
nike
Sum of Sales
60
60
Count of Sales
4
4
puma
Sum of Sales
10
50
60
Count of Sales
1
2
3
I've looked at two approaches:
1. Putting the values into an object like this:
json_build_object(
'Sum of Sales', SUM(sales),
'Count of Sales', COUNT(sales)
) as "Values"
And then in some way "expanding" them as rows under "Values" column.
2. Using unnest in some way but unsure about that approach.
Important requirement:
The values in brand and gender are unknown so the values from brand (nike, etc) and gender (male, etc) are generated dynamically.
Does anyone know how to do this?
For context; this is a continuation of this question:
Get Row Totals for Dynamically Created Pivoted Table

Answer 1

1. Splitting the resulting rows in 2 subrows in not a big deal :
SELECT brand,
label,
jsonb_object_agg(
gender,
json_build_object(label, total)
) AS gender,
SUM(total) AS "Total"
FROM (
SELECT brand,
gender,
sum(sales) :: integer AS total,
'Sum of Sales' AS label
FROM cross_table
GROUP BY ROLLUP(brand), gender
UNION ALL
SELECT brand,
gender,
count(sales) :: integer,
'Count of Sales'
FROM cross_table
GROUP BY ROLLUP(brand), gender
) AS a
GROUP BY brand, label
ORDER BY brand, label ;
2. Splitting the resulting columns in 2 or more subcolumns may be more touchy :
2.A Static list of gender values
If gender has only two values "male" and "woman" then :
CREATE TYPE gender AS (male integer, woman integer) ;
SELECT brand,
label,
(jsonb_populate_record(null :: gender, jsonb_object_agg(lower(gender),total))).*,
SUM(total) AS "Total"
FROM (
SELECT brand,
gender,
sum(sales) :: integer AS total,
'Sum of Sales' AS label
FROM cross_table
GROUP BY ROLLUP(brand), gender
UNION ALL
SELECT brand,
gender,
count(sales) :: integer,
'Count of Sales'
FROM cross_table
GROUP BY ROLLUP(brand), gender
) AS a
GROUP BY brand, label
ORDER BY brand, label ;
2.B Dynamic list of gender values
If the gender list of values may vary in time, then :
We need to dynamically create and update the composite type gender from a trigger on table cross_table :
CREATE OR REPLACE FUNCTION trigger_cross_table ()
RETURNS trigger LANGUAGE plpgsql AS $$
DECLARE
_columns text ;
BEGIN
SELECT string_agg(DISTINCT gender || ' integer', ',')
INTO _columns
FROM cross_table ;
DROP TYPE IF EXISTS gender ;
EXECUTE 'CREATE TYPE gender (' || _columns || '(' ;
RETURN NULL ;
END ; $$ ;
CREATE OR REPLACE TRIGGER trigger_cross_table AFTER INSERT OR UPDATE OF gender OR DELETE
ON cross_table FOR EACH STATEMENT EXECUTE FUNCTION trigger_cross_table() ;
The final query is the same :
SELECT brand,
label,
(jsonb_populate_record(null :: gender, jsonb_object_agg(lower(gender),total))).*,
SUM(total) AS "Total"
FROM (
SELECT brand,
gender,
sum(sales) :: integer AS total,
'Sum of Sales' AS label
FROM cross_table
GROUP BY ROLLUP(brand), gender
UNION ALL
SELECT brand,
gender,
count(sales) :: integer,
'Count of Sales'
FROM cross_table
GROUP BY ROLLUP(brand), gender
) AS a
GROUP BY brand, label
ORDER BY brand, label ;
see dbfiddle