MAP_FROM_ENTRIES

Description

The MAP_FROM_ENTRIES function is used to create a map type from an array. The elements of the input array need to conform to the format of the map_entries function, where each element is a struct containing key and value properties.

Parameters

array: Input parameter, type array<struct<key:K, value:V>>, representing an array containing multiple structs, each with key and value properties.

Return Value

Returns a result of type map<K, V>, where K represents the type of the key and V represents the type of the value.

Example Usage

Create an array containing two elements, each of which is a struct with two properties: key and value.

SELECT MAP_FROM_ENTRIES(ARRAY( NAMED_STRUCT('key',1, 'value','a'), NAMED_STRUCT('key',2, 'value','b') ));

Return Results:

{ 1:"a", 2:"b" }

Create an array containing three elements, where the element type is a structure, and the structure contains different types of keys and values.

SELECT MAP_FROM_ENTRIES(ARRAY( NAMED_STRUCT('key',1, 'value','apple' ), NAMED_STRUCT('key',2, 'value','carrot'), NAMED_STRUCT('key',3, 'value','dog') ));

Return Results:

{ 1:"apple", 2:"carrot", 3:"dog" }

Note: In the above example, the extra attribute will not be included in the final map because we only care about the key and value attributes.

Notes

Each struct in the input array must have key and value attributes, otherwise the function will fail.
The type of the key needs to be unique, and there cannot be duplicate key values, otherwise the later key values will overwrite the earlier key values.