ClickHouse/tests/queries/0_stateless/01591_window_functions.sql

-- { echo }

set allow_experimental_window_functions = 1;

-- just something basic
select number, count() over (partition by intDiv(number, 3) order by number) from numbers(10);

-- proper calculation across blocks
select number, max(number) over (partition by intDiv(number, 3) order by number desc) from numbers(10) settings max_block_size = 2;

-- not a window function
select number, abs(number) over (partition by toString(intDiv(number, 3))) from numbers(10); -- { serverError 63 }

-- no partition by
select number, avg(number) over (order by number) from numbers(10);

-- no order by
select number, quantileExact(number) over (partition by intDiv(number, 3)) from numbers(10);

-- can add an alias after window spec
select number, quantileExact(number) over (partition by intDiv(number, 3)) q from numbers(10);

-- can't reference it yet -- the window functions are calculated at the
-- last stage of select, after all other functions.
select q * 10, quantileExact(number) over (partition by intDiv(number, 3)) q from numbers(10); -- { serverError 47 }

-- must work in WHERE if you wrap it in a subquery
select * from (select count(*) over () c from numbers(3)) where c > 0;

-- should work in ORDER BY
select number, max(number) over (partition by intDiv(number, 3) order by number desc) m from numbers(10) order by m desc, number;

-- also works in ORDER BY if you wrap it in a subquery
select * from (select count(*) over () c from numbers(3)) order by c;

-- Example with window function only in ORDER BY. Here we make a rank of all
-- numbers sorted descending, and then sort by this rank descending, and must get
-- the ascending order.
select * from (select * from numbers(5) order by rand()) order by count() over (order by number desc) desc;

-- Aggregate functions as window function arguments. This query is semantically
-- the same as the above one, only we replace `number` with
-- `any(number) group by number` and so on.
select * from (select * from numbers(5) order by rand()) group by number order by sum(any(number + 1)) over (order by min(number) desc) desc;

-- different windows
-- an explain test would also be helpful, but it's too immature now and I don't
-- want to change reference all the time
select number, max(number) over (partition by intDiv(number, 3) order by number desc), count(number) over (partition by intDiv(number, 5) order by number) as m from numbers(31) order by number settings max_block_size = 2;

-- two functions over the same window
-- an explain test would also be helpful, but it's too immature now and I don't
-- want to change reference all the time
select number, max(number) over (partition by intDiv(number, 3) order by number desc), count(number) over (partition by intDiv(number, 3) order by number desc) as m from numbers(7) order by number settings max_block_size = 2;

-- check that we can work with constant columns
select median(x) over (partition by x) from (select 1 x);

-- an empty window definition is valid as well
select groupArray(number) over () from numbers(3);

-- This one tests we properly process the window  function arguments.
-- Seen errors like 'column `1` not found' from count(1).
select count(1) over (), max(number + 1) over () from numbers(3);

-- Should work in DISTINCT
select distinct sum(0) over () from numbers(2);
select distinct any(number) over () from numbers(2);

-- Various kinds of aliases are properly substituted into various parts of window
-- function definition.
with number + 1 as x select intDiv(number, 3) as y, sum(x + y) over (partition by y order by x) from numbers(7);