Map Functions

element_at(map(K, V), key) → V

Returns value for given key, or NULL if the key is not contained in the map.

map(K, V, K, V, ...) -> map(K, V)

Returns a map created using the given key/value pairs. Keys are not allowed to be null.

SELECT map(1, 2, 3, 4); -- {1 -> 2, 3 -> 4}

SELECT map(array(1, 2), array(3, 4)); -- {[1, 2] -> [3, 4]}

map_concat(map1(K, V), map2(K, V), ..., mapN(K, V)) -> map(K, V)

Returns the union of all the given maps. If a key is found in multiple given maps, by default that key’s value in the resulting map comes from the last one of those maps. If configuration throw_exception_on_duplicate_map_keys is set true, throws exception for duplicate keys. Allows single map input.

SELECT map_concat(map(1, 'a', 2, 'b'), map(3, 'c')); -- {1 -> 'a', 2 -> 'b', 3 -> 'c'}
SELECT map_concat(map(1, 'a', 2, 'b'), map(3, NULL)); -- {1 -> 'a', 2 -> 'b', 3 -> NULL}
SELECT map_concat(map(1, 'a', 2, 'b')); -- {1 -> 'a', 2 -> 'b'}
SELECT map_concat(map(1, 'a', 2, 'b'), map(3, 'c', 2, 'd')); -- {1 -> 'a', 2 -> 'd', 3 -> 'c'} (LAST_WIN behavior)
SELECT map_concat(map(1, 'a', 2, 'b'), map(3, 'c', 2, 'd')); --  "Duplicate map key 2 was found" (EXCEPTION behavior)

map_entries(map(K, V)) -> array(row(K, V))

Returns an array of all entries in the given map.

SELECT map_entries(MAP(ARRAY[1, 2], ARRAY['x', 'y'])); -- [ROW(1, 'x'), ROW(2, 'y')]

map_filter(map(K, V), func) -> map(K, V)

Filters entries in a map using the function.

SELECT map_filter(map(1, 0, 2, 2, 3, -1), (k, v) -> k > v); -- {1 -> 0, 3 -> -1}

map_from_arrays(array(K), array(V)) -> map(K, V)

Creates a map with a pair of the given key/value arrays. All elements in keys should not be null. If key size != value size will throw exception that key and value must have the same length.:

SELECT map_from_arrays(array(1.0, 3.0), array('2', '4')); -- {1.0 -> 2, 3.0 -> 4}

map_keys(x(K, V)) -> array(K)

Returns all the keys in the map x.

map_values(x(K, V)) -> array(V)

Returns all the values in the map x.

map_zip_with(map(K, V1), map(K, V2), function(K, V1, V2, V3)) -> map(K, V3)

Merges the two given maps into a single map by applying function to the pair of values with the same key. For keys only presented in one map, NULL will be passed as the value for the missing key.

SELECT map_zip_with(MAP(ARRAY[1, 2, 3], ARRAY['a', 'b', 'c']), -- {1 -> ad, 2 -> be, 3 -> cf}
                    MAP(ARRAY[1, 2, 3], ARRAY['d', 'e', 'f']),
                    (k, v1, v2) -> concat(v1, v2));
SELECT map_zip_with(MAP(ARRAY['k1', 'k2'], ARRAY[1, 2]), -- {k1 -> ROW(1, null), k2 -> ROW(2, 4), k3 -> ROW(null, 9)}
                    MAP(ARRAY['k2', 'k3'], ARRAY[4, 9]),
                    (k, v1, v2) -> (v1, v2));
SELECT map_zip_with(MAP(ARRAY['a', 'b', 'c'], ARRAY[1, 8, 27]), -- {a -> a1, b -> b4, c -> c9}
                    MAP(ARRAY['a', 'b', 'c'], ARRAY[1, 2, 3]),
                    (k, v1, v2) -> k || CAST(v1/v2 AS VARCHAR));

size(map(K, V), legacySizeOfNull) → integer

Returns the size of the input map. Returns null for null input if legacySizeOfNull is set to false. Otherwise, returns -1 for null input.

SELECT size(map(array(1, 2), array(3, 4)), true); -- 2
SELECT size(NULL, true); -- -1
SELECT size(NULL, false); -- NULL