SET extra_float_digits = 0;
-- Create a table to store x and y values
CREATE TABLE xicor_test (
                            id serial PRIMARY KEY,
                            x float8,
                            y float8
);
-- Insert 5 rows of data with sample x and y values
INSERT INTO xicor_test (x, y)
VALUES
    (1.0, 2.0),
    (2.5, 3.5),
    (3.0, 4.0),
    (4.5, 5.5),
    (5.0, 6.0);
-- Query to calculate the Xi correlation using the aggregate function
SELECT xicor(x, y) FROM xicor_test;
 xicor 
-------
   0.5
(1 row)