-- Migrated from DuckDB test: test/sql/aggregate/aggregates/test_corr.test
-- Test CORR operator (correlation coefficient)
-- Corner cases
SELECT corr(NULL,NULL);

+-----------------+
| corr(NULL,NULL) |
+-----------------+
|                 |
+-----------------+

-- Single value returns NULL
SELECT corr(1,1);

+-------------------------+
| corr(Int64(1),Int64(1)) |
+-------------------------+
|                         |
+-------------------------+

-- Test with table
CREATE TABLE aggr(k INT, v DECIMAL(10,2), v2 DECIMAL(10, 2), ts TIMESTAMP TIME INDEX);

Affected Rows: 0

INSERT INTO aggr VALUES
    (1, 10, null, 1000),
    (2, 10, 11, 2000),
    (2, 20, 22, 3000),
    (2, 25, null, 4000),
    (2, 30, 35, 5000);

Affected Rows: 5

SELECT k, corr(v, v2) FROM aggr GROUP BY k ORDER BY k;

+---+----------------------+
| k | corr(aggr.v,aggr.v2) |
+---+----------------------+
| 1 |                      |
| 2 | 0.9988445981121536   |
+---+----------------------+

SELECT corr(v, v2) FROM aggr;

+----------------------+
| corr(aggr.v,aggr.v2) |
+----------------------+
| 0.9988445981121532   |
+----------------------+

-- Test with integer values
CREATE TABLE corr_test(x INTEGER, y INTEGER, ts TIMESTAMP TIME INDEX);

Affected Rows: 0

INSERT INTO corr_test VALUES
    (1, 2, 1000),
    (2, 4, 2000),
    (3, 6, 3000),
    (4, 8, 4000),
    (5, 10, 5000);

Affected Rows: 5

-- Perfect positive correlation
SELECT corr(x, y) FROM corr_test;

+-------------------------------+
| corr(corr_test.x,corr_test.y) |
+-------------------------------+
| 0.9999999999999999            |
+-------------------------------+

-- Test with negative correlation
INSERT INTO corr_test VALUES
    (6, 5, 6000),
    (7, 3, 7000),
    (8, 1, 8000);

Affected Rows: 3

SELECT corr(x, y) FROM corr_test;

+-------------------------------+
| corr(corr_test.x,corr_test.y) |
+-------------------------------+
| -0.12452312927991684          |
+-------------------------------+

-- cleanup
DROP TABLE aggr;

Affected Rows: 0

DROP TABLE corr_test;

Affected Rows: 0