SELECT array_to_percentile('{}'::float[], 0.2);
 array_to_percentile 
---------------------
                    
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::smallint[], 0.2);
 array_to_percentile 
---------------------
                   1
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::integer[], 0.2);
 array_to_percentile 
---------------------
                   1
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::bigint[], 0.2);
 array_to_percentile 
---------------------
                   1
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::real[], 0.2);
 array_to_percentile 
---------------------
                   1
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::float[], 0.2);
 array_to_percentile 
---------------------
                   1
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::text[], 0.2);
ERROR:  Percentile subject must be SMALLINT, INTEGER, BIGINT, REAL, or DOUBLE PRECISION values
SELECT array_to_percentile('{1,1,5,2,0,7}'::float[], 0);
 array_to_percentile 
---------------------
                   0
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::float[], 1);
 array_to_percentile 
---------------------
                   7
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::float[], 0.5);
 array_to_percentile 
---------------------
                 1.5
(1 row)

SELECT array_to_percentile('{1,2,5,3,0}'::float[], 0.5);
 array_to_percentile 
---------------------
                   2
(1 row)

SELECT array_to_percentile('{1,1,5,2,0,7}'::float[], -0.2);
ERROR:  Percent must be between 0 and 1
SELECT array_to_percentile('{1,1,5,2,0,7}'::float[], 1.2);
ERROR:  Percent must be between 0 and 1