all_match

Description

Returns whether all elements of an array match the given predicate.

• Returns true (1) if all the elements match the predicate (a special case is when the array is empty).

• Returns false (0) if one or more elements do not match.

• Returns NULL if the predicate returns NULL for one or more elements and true for all other elements.

This function is supported from v3.0.6 onwards.

Syntax

all_match(lambda_function, arr1, arr2...)

Returns whether all elements of arr1 match the given predicate in the lambda function.

Parameters

• arr1: the array to match.

• arrN: optional arrays used in the lambda function.

• lambda_function: the lambda function used to match values.

Return value

Returns a BOOLEAN value.

Usage notes

• The lambda function follows the usage notes in array_map().
• If the input array is null or the lambda function results in null, null is returned.
• If arr1 is empty, true is returned.
• To apply this function to MAP, rewrite all_match((k,v)->k>v,map) to all_match(map_values(transform_values((k,v)->k>v, map))). For example, select all_match(map_values(transform_values((k,v)->k>v, map{2:1}))); returns 1.

Examples

Check whether all elements in x are less than the elements in y.

select all_match((x,y) -> x < y, [1,2,-8], [4,5,6]);
+---------------------------------------------------+
| all_match((x, y) -> x < y, [1, 2, -8], [4, 5, 6]) |
+---------------------------------------------------+
|                                                 1 |
+---------------------------------------------------+

select all_match((x,y) -> x < y, [1,2,null], [4,5,6]);
+-----------------------------------------------------+
| all_match((x, y) -> x < y, [1, 2, NULL], [4, 5, 6]) |
+-----------------------------------------------------+
|                                                NULL |
+-----------------------------------------------------+

select all_match((x,y) -> x < y, [1,2,8], [4,5,6]);
+--------------------------------------------------+
| all_match((x, y) -> x < y, [1, 2, 8], [4, 5, 6]) |
+--------------------------------------------------+
|                                                0 |
+--------------------------------------------------+

select all_match((x,y) -> x < y, [], []);
+------------------------------------+
| all_match((x, y) -> x < y, [], []) |
+------------------------------------+
|                                  1 |
+------------------------------------+

select all_match((x,y) -> x < y, null, [4,5,6]);
+---------------------------------------------+
| all_match((x, y) -> x < y, NULL, [4, 5, 6]) |
+---------------------------------------------+
|                                        NULL |
+---------------------------------------------+