--
-- num_nulls()
--
SELECT num_nonnulls(NULL);
 num_nonnulls 
--------------
            0
(1 row)

SELECT num_nonnulls('1');
 num_nonnulls 
--------------
            1
(1 row)

SELECT num_nonnulls(NULL::text);
 num_nonnulls 
--------------
            0
(1 row)

SELECT num_nonnulls(NULL::text, NULL::int);
 num_nonnulls 
--------------
            0
(1 row)

SELECT num_nonnulls(1, 2, NULL::text, NULL::point, '', int8 '9', 1.0 / NULL);
 num_nonnulls 
--------------
            4
(1 row)

SELECT num_nonnulls(VARIADIC '{1,2,NULL,3}'::int[]);
 num_nonnulls 
--------------
            3
(1 row)

SELECT num_nonnulls(VARIADIC '{"1","2","3","4"}'::text[]);
 num_nonnulls 
--------------
            4
(1 row)

SELECT num_nonnulls(VARIADIC ARRAY(SELECT CASE WHEN i <> 40 THEN i END FROM generate_series(1, 100) i));
 num_nonnulls 
--------------
           99
(1 row)

SELECT num_nulls(NULL);
 num_nulls 
-----------
         1
(1 row)

SELECT num_nulls('1');
 num_nulls 
-----------
         0
(1 row)

SELECT num_nulls(NULL::text);
 num_nulls 
-----------
         1
(1 row)

SELECT num_nulls(NULL::text, NULL::int);
 num_nulls 
-----------
         2
(1 row)

SELECT num_nulls(1, 2, NULL::text, NULL::point, '', int8 '9', 1.0 / NULL);
 num_nulls 
-----------
         3
(1 row)

SELECT num_nulls(VARIADIC '{1,2,NULL,3}'::int[]);
 num_nulls 
-----------
         1
(1 row)

SELECT num_nulls(VARIADIC '{"1","2","3","4"}'::text[]);
 num_nulls 
-----------
         0
(1 row)

SELECT num_nulls(VARIADIC ARRAY(SELECT CASE WHEN i <> 40 THEN i END FROM generate_series(1, 100) i));
 num_nulls 
-----------
         1
(1 row)

-- special cases
SELECT num_nonnulls(VARIADIC NULL::text[]);
 num_nonnulls 
--------------
             
(1 row)

SELECT num_nonnulls(VARIADIC '{}'::int[]);
 num_nonnulls 
--------------
            0
(1 row)

SELECT num_nulls(VARIADIC NULL::text[]);
 num_nulls 
-----------
          
(1 row)

SELECT num_nulls(VARIADIC '{}'::int[]);
 num_nulls 
-----------
         0
(1 row)

-- should fail, one or more arguments is required
SELECT num_nonnulls();
ERROR:  function num_nonnulls() does not exist
LINE 1: SELECT num_nonnulls();
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
SELECT num_nulls();
ERROR:  function num_nulls() does not exist
LINE 1: SELECT num_nulls();
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
--
-- Test adding a support function to a subject function
--
CREATE FUNCTION my_int_eq(int, int) RETURNS bool
  LANGUAGE internal STRICT IMMUTABLE PARALLEL SAFE
  AS $$int4eq$$;
-- By default, planner does not think that's selective
EXPLAIN (COSTS OFF)
SELECT * FROM tenk1 a JOIN tenk1 b ON a.unique1 = b.unique1
WHERE my_int_eq(a.unique2, 42);
                  QUERY PLAN                  
----------------------------------------------
 Hash Join
   Hash Cond: (b.unique1 = a.unique1)
   ->  Seq Scan on tenk1 b
   ->  Hash
         ->  Seq Scan on tenk1 a
               Filter: my_int_eq(unique2, 42)
(6 rows)

-- With support function that knows it's int4eq, we get a different plan
ALTER FUNCTION my_int_eq(int, int) SUPPORT test_support_func;
EXPLAIN (COSTS OFF)
SELECT * FROM tenk1 a JOIN tenk1 b ON a.unique1 = b.unique1
WHERE my_int_eq(a.unique2, 42);
                   QUERY PLAN                    
-------------------------------------------------
 Nested Loop
   ->  Seq Scan on tenk1 a
         Filter: my_int_eq(unique2, 42)
   ->  Index Scan using tenk1_unique1 on tenk1 b
         Index Cond: (unique1 = a.unique1)
(5 rows)

-- Also test non-default rowcount estimate
CREATE FUNCTION my_gen_series(int, int) RETURNS SETOF integer
  LANGUAGE internal STRICT IMMUTABLE PARALLEL SAFE
  AS $$generate_series_int4$$
  SUPPORT test_support_func;
EXPLAIN (COSTS OFF)
SELECT * FROM tenk1 a JOIN my_gen_series(1,1000) g ON a.unique1 = g;
               QUERY PLAN               
----------------------------------------
 Hash Join
   Hash Cond: (g.g = a.unique1)
   ->  Function Scan on my_gen_series g
   ->  Hash
         ->  Seq Scan on tenk1 a
(5 rows)

EXPLAIN (COSTS OFF)
SELECT * FROM tenk1 a JOIN my_gen_series(1,10) g ON a.unique1 = g;
                   QUERY PLAN                    
-------------------------------------------------
 Nested Loop
   ->  Function Scan on my_gen_series g
   ->  Index Scan using tenk1_unique1 on tenk1 a
         Index Cond: (unique1 = g.g)
(4 rows)