# name: test/sql/aggregate/aggregates/test_skewness.test
# description: Test skewness aggregate
# group: [aggregates]

statement ok
PRAGMA enable_verification

#Corner cases
statement error
select skewness()
----

query I
select skewness(NULL)
----
NULL

query I
select skewness(1)
----
NULL

statement error
select skewness(*)
----

# Constant Value
query I
select skewness (10) from range (5)
----
NAN

#Empty Table
query I
select skewness (10) from range (5) where 1 == 0
----
NULL

# out of range
statement error
select skewness(i) from (values (-2e307), (0), (2e307)) tbl(i)
----

statement ok
create table aggr(k int, v decimal(10,2), v2 decimal(10, 2));

statement ok
insert into aggr values
    (1, 10, null),
    (2, 10, 11),
    (2, 10, 15),
    (2, 10, 18),
    (2, 20, 22),
    (2, 20, 25),
    (2, 25, null),
    (2, 30, 35),
    (2, 30, 40),
    (2, 30, 50),
    (2, 30, 51);

query III
select skewness(k), skewness(v), skewness(v2) from aggr
----
-3.316625	-0.163444	0.365401

query I
select skewness(v2) from aggr group by v ORDER BY ALL
----
-0.423273
-0.330141
NULL
NULL

# Window Function
query I
select skewness(v2) over (partition by v)
    from aggr order by v;
----
-0.423273
-0.423273
-0.423273
-0.423273
NULL
NULL
NULL
-0.330141
-0.330141
-0.330141
-0.330141