SQL: alternatives and substitutions for GROUPING SETS and PIVOT - sql

Question

I've got code like this:
SELECT id, YEAR(datek) AS YEAR, COUNT(*) AS NUM
FROM Orders
GROUP BY GROUPING SETS
(
(id, YEAR(datek)),
id,
YEAR(datek),
()
);
It gives me this output:
1 NULL 4
2 NULL 11
3 NULL 6
NULL NULL 21
1 2006 36
2 2006 56
3 2006 51
NULL 2006 143
1 2007 130
2 2007 143
3 2007 125
NULL 2007 398
1 2008 79
2 2008 116
3 2008 73
NULL 2008 268
NULL NULL 830
1 NULL 249
2 NULL 326
3 NULL 255
What I need to do is write it without "grouping sets" (nor cube or rollup) but with the same result. I thought about writing three different queries and join them with "union". I try something like "null" in group by settings but it does not work.
SELECT id, YEAR(datek) AS rok, COUNT(*) AS NUM
FROM Orders
GROUP BY id, YEAR(datek)
UNION
SELECT id, YEAR(datek) AS rok, COUNT(*) AS NUM
FROM Orders
GROUP BY id, null
order by id, YEAR(datek)
I also have a question about "PIVOT". What kind of syntax can replace query with "PIVOT"?
Thanks for your time and all the answers!

Answer 1

You are right in that you need separate queries, although you actually need 4, and rather than GROUP BY NULL, just group by the columns in the corresponding grouping set, and replace the column in the SELECT with NULL:
SELECT id, YEAR(datek) AS rok, COUNT(*) AS NUM
FROM Orders
GROUP BY id, YEAR(datek)
UNION ALL
SELECT id, NULL, COUNT(*) AS NUM
FROM Orders
GROUP BY id
UNION ALL
SELECT NULL, YEAR(datek), COUNT(*) AS NUM
FROM Orders
GROUP BY YEAR(datek)
UNION ALL
SELECT NULL, NULL, COUNT(*) AS NUM
FROM Orders
ORDER BY ID, Rok
With regard to a replacement for PIVOT I think the best alternative is to use a conditional aggregate, e.g. instead of:
SELECT pvt.SomeGroup,
pvt.[A],
pvt.[B],
pvt.[C]
FROM T
PIVOT (SUM(Val) FOR Col IN ([A], [B], [C])) AS pvt;
You would use:
SELECT T.SomeGroup,
[A] = SUM(CASE WHEN T.Col = 'A' THEN T.Val ELSE 0 END),
[B] = SUM(CASE WHEN T.Col = 'B' THEN T.Val ELSE 0 END),
[C] = SUM(CASE WHEN T.Col = 'C' THEN T.Val ELSE 0 END)
FROM T
GROUP BY T.SomeGroup;