Sum and Running Sum, Distinct and Running Distinct - sql

Question

I want to calculate sum, running sum, distinct, running distinct - preferably all in one query.
http://sqlfiddle.com/#!18/65eff/1
create table test (store int, day varchar(10), food varchar(10), quantity int)
insert into test select 101, '2021-01-01', 'rice', 1
insert into test select 101, '2021-01-01', 'rice', 1
insert into test select 101, '2021-01-01', 'rice', 2
insert into test select 101, '2021-01-01', 'fruit', 2
insert into test select 101, '2021-01-01', 'water', 3
insert into test select 101, '2021-01-01', 'fruit', 1
insert into test select 101, '2021-01-01', 'salt', 2
insert into test select 101, '2021-01-02', 'rice', 1
insert into test select 101, '2021-01-02', 'rice', 2
insert into test select 101, '2021-01-02', 'fruit', 1
insert into test select 101, '2021-01-02', 'pepper', 4
Uniques (distinct) & Total (sum) are simple:
select store, day, count(distinct food) as uniques, sum(quantity) as total
from test
group by store, day
But I want output to be :
store
day
uniques
run_uniques
total
run_total
101
2021-01-01
4
4
12
12
101
2021-01-02
3
5
10
22
I tried a self-join with t.day >= prev.day to get cumulative/running data, but it's causing double-counting.

Answer 1

First off: always store data in the correct data type, day should be a date column.
Calculating a running sum of sum(quantity) aggregate is quite simple, you just nest it inside a window function: SUM(SUM(...)) OVER (...).
Calculating the running number of unique food per store is more complicated because you want the rolling number of unique items before grouping, and there is no COUNT(DISTINCT window function in SQL Server (which is what I'm using).
So I've gone with calculating a row_number() for each store and food across all days, then we just sum up the number of times we get 1 i.e. this is the first time we've seen this food.
SELECT
t.store,
t.day,
uniques = COUNT(DISTINCT t.food),
run_uniques = SUM(SUM(CASE WHEN t.rn = 1 THEN 1 ELSE 0 END))
OVER (PARTITION BY t.store ORDER BY t.day ROWS UNBOUNDED PRECEDING),
total = SUM(t.quantity),
run_total = SUM(SUM(t.quantity))
OVER (PARTITION BY t.store ORDER BY t.day ROWS UNBOUNDED PRECEDING)
FROM (
SELECT *,
ROW_NUMBER() OVER (PARTITION BY store, food ORDER BY day) rn
FROM test
) t
GROUP BY t.store, t.day;