# name: test/sql/aggregate/aggregates/test_covar.test
# description: Test COVAR operators
# group: [aggregates]

# test incorrect usage of COVAR_POP function
statement error
SELECT COVAR_POP()
----

statement error
SELECT COVAR_POP(1, 2, 3)
----

statement error
SELECT COVAR_POP(COVAR_POP(1))
----

# test incorrect usage of COVAR_SAMP function
statement error
SELECT COVAR_SAMP()
----

statement error
SELECT COVAR_SAMP(1, 2, 3)
----

statement error
SELECT COVAR_SAMP(COVAR_SAMP(1))
----

# test population covariance on scalar values
query RRRR
SELECT COVAR_POP(3,3), COVAR_POP(NULL,3), COVAR_POP(3,NULL), COVAR_POP(NULL,NULL)
----
0.000000
NULL
NULL
NULL

# test sample covariance on scalar values
query RRRR
SELECT COVAR_SAMP(3,3), COVAR_SAMP(NULL,3), COVAR_SAMP(3,NULL), COVAR_SAMP(NULL,NULL)
----
NULL
NULL
NULL
NULL

# test population covariance on a sequence
statement ok
CREATE SEQUENCE seqx;

statement ok
CREATE SEQUENCE seqy;

query R
SELECT COVAR_POP(nextval('seqx'),nextval('seqy'))
----
0.000000

query R
SELECT COVAR_POP(nextval('seqx'),nextval('seqy'))
----
0.000000

# test population covariance on a set of values
statement ok
CREATE TABLE integers(x INTEGER, y INTEGER);

statement ok
INSERT INTO integers VALUES (10,NULL), (10,11), (20,22), (25,NULL), (30,35)

query RRRRR
SELECT COVAR_POP(x,y), COVAR_POP(x,1), COVAR_POP(1,y), COVAR_POP(x,NULL), COVAR_POP(NULL,y) FROM integers
----
80.000000
0.000000
0.000000
NULL
NULL

query RRRRR
SELECT COVAR_SAMP(x,y), COVAR_SAMP(x,1), COVAR_SAMP(1,y), COVAR_SAMP(x,NULL), COVAR_SAMP(NULL,y) FROM integers
----
120.000000
0.000000
0.000000
NULL
NULL

# test covar on empty set
query RR
SELECT COVAR_POP(x,y), COVAR_SAMP(x,y) FROM integers WHERE x > 100
----
NULL
NULL

# test covar with only null inputs
query RR
SELECT COVAR_POP(NULL, NULL), COVAR_SAMP(NULL, NULL) FROM integers
----
NULL
NULL