-- smallint max lots
SELECT vec_to_max(smallints) FROM measurements WHERE sensor_id IN (1, 2, 3, 4);
 vec_to_max 
------------
 {1,2,3}
(1 row)

-- smallint max none
SELECT vec_to_max(smallints) FROM measurements WHERE sensor_id = -1;
 vec_to_max 
------------
 
(1 row)

-- smallint max one null
SELECT vec_to_max(smallints) FROM measurements WHERE sensor_id = 1;
 vec_to_max 
------------
 
(1 row)

-- smallint max array of nulls
SELECT vec_to_max(smallints) FROM measurements WHERE sensor_id = 2;
    vec_to_max    
------------------
 {NULL,NULL,NULL}
(1 row)

-- smallint max one not-null
SELECT vec_to_max(smallints) FROM measurements WHERE sensor_id = 4;
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- smallint max array of nulls and one other
SELECT vec_to_max(smallints) FROM measurements WHERE sensor_id IN (2, 4);
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- int max lots
SELECT vec_to_max(ints) FROM measurements WHERE sensor_id IN (1, 2, 3, 4);
 vec_to_max 
------------
 {1,2,3}
(1 row)

-- int max none
SELECT vec_to_max(ints) FROM measurements WHERE sensor_id = -1;
 vec_to_max 
------------
 
(1 row)

-- int max one null
SELECT vec_to_max(ints) FROM measurements WHERE sensor_id = 1;
 vec_to_max 
------------
 
(1 row)

-- int max array of nulls
SELECT vec_to_max(ints) FROM measurements WHERE sensor_id = 2;
    vec_to_max    
------------------
 {NULL,NULL,NULL}
(1 row)

-- int max one not-null
SELECT vec_to_max(ints) FROM measurements WHERE sensor_id = 4;
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- int max array of nulls and one other
SELECT vec_to_max(ints) FROM measurements WHERE sensor_id IN (2, 4);
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- bigint max lots
SELECT vec_to_max(bigints) FROM measurements WHERE sensor_id IN (1, 2, 3, 4);
 vec_to_max 
------------
 {1,2,3}
(1 row)

-- bigint max none
SELECT vec_to_max(bigints) FROM measurements WHERE sensor_id = -1;
 vec_to_max 
------------
 
(1 row)

-- bigint max one null
SELECT vec_to_max(bigints) FROM measurements WHERE sensor_id = 1;
 vec_to_max 
------------
 
(1 row)

-- bigint max array of nulls
SELECT vec_to_max(bigints) FROM measurements WHERE sensor_id = 2;
    vec_to_max    
------------------
 {NULL,NULL,NULL}
(1 row)

-- bigint max one not-null
SELECT vec_to_max(bigints) FROM measurements WHERE sensor_id = 4;
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- bigint max array of nulls and one other
SELECT vec_to_max(bigints) FROM measurements WHERE sensor_id IN (2, 4);
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- real max lots
SELECT vec_to_max(reals) FROM measurements WHERE sensor_id IN (1, 2, 3, 4);
 vec_to_max 
------------
 {1,2,3}
(1 row)

-- real max none
SELECT vec_to_max(reals) FROM measurements WHERE sensor_id = -1;
 vec_to_max 
------------
 
(1 row)

-- real max one null
SELECT vec_to_max(reals) FROM measurements WHERE sensor_id = 1;
 vec_to_max 
------------
 
(1 row)

-- real max array of nulls
SELECT vec_to_max(reals) FROM measurements WHERE sensor_id = 2;
    vec_to_max    
------------------
 {NULL,NULL,NULL}
(1 row)

-- real max one not-null
SELECT vec_to_max(reals) FROM measurements WHERE sensor_id = 4;
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- real max array of nulls and one other
SELECT vec_to_max(reals) FROM measurements WHERE sensor_id IN (2, 4);
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- float8 max lots
SELECT vec_to_max(floats) FROM measurements WHERE sensor_id IN (1, 2, 3, 4);
 vec_to_max 
------------
 {1,2,3}
(1 row)

-- float8 max none
SELECT vec_to_max(floats) FROM measurements WHERE sensor_id = -1;
 vec_to_max 
------------
 
(1 row)

-- float8 max one null
SELECT vec_to_max(floats) FROM measurements WHERE sensor_id = 1;
 vec_to_max 
------------
 
(1 row)

-- float8 max array of nulls
SELECT vec_to_max(floats) FROM measurements WHERE sensor_id = 2;
    vec_to_max    
------------------
 {NULL,NULL,NULL}
(1 row)

-- float8 max one not-null
SELECT vec_to_max(floats) FROM measurements WHERE sensor_id = 4;
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- float8 max array of nulls and one other
SELECT vec_to_max(floats) FROM measurements WHERE sensor_id IN (2, 4);
 vec_to_max 
------------
 {1,NULL,2}
(1 row)

-- numeric max lots
SELECT vec_to_max(nums) FROM measurements WHERE sensor_id IN (1, 2, 3, 4);
    vec_to_max    
------------------
 {1.23,2.34,3.45}
(1 row)

-- numeric max none
SELECT vec_to_max(nums) FROM measurements WHERE sensor_id = -1;
 vec_to_max 
------------
 
(1 row)

-- numeric max one null
SELECT vec_to_max(nums) FROM measurements WHERE sensor_id = 1;
 vec_to_max 
------------
 
(1 row)

-- numeric max array of nulls
SELECT vec_to_max(nums) FROM measurements WHERE sensor_id = 2;
    vec_to_max    
------------------
 {NULL,NULL,NULL}
(1 row)

-- numeric max one not-null
SELECT vec_to_max(nums) FROM measurements WHERE sensor_id = 4;
    vec_to_max    
------------------
 {1.23,NULL,2.34}
(1 row)

-- numeric max array of nulls and one other
SELECT vec_to_max(nums) FROM measurements WHERE sensor_id IN (2, 4);
    vec_to_max    
------------------
 {1.23,NULL,2.34}
(1 row)

-- numeric max data 01
-- results expected to match:
-- WITH di AS (
--   SELECT idx_i, max(val_i) AS max_i
--   FROM measurements2 d, unnest(d.data_i) WITH ORDINALITY AS a(val_i, idx_i)
--   GROUP BY idx_i
-- )
-- SELECT array_agg(max_i ORDER BY idx_i) AS data_i_max FROM di
SELECT vec_to_max(data_i) FROM measurements2;
                                  vec_to_max                                   
-------------------------------------------------------------------------------
 {23200619,48587.514387,234.99962,50.5,13161880,1,332.20728,23730754,23623545}
(1 row)