HLL_FROM_BASE64

Description

Converts a base64-encoded string (usually the result of the HLL_TO_BASE64 function) into an HLL. If the input string is invalid or NULL, the function returns NULL.

Syntax

HLL_FROM_BASE64(<input>)

Parameters

Parameter	Description
<input>	A base64-encoded string, typically generated by the HLL_TO_BASE64 function. If the input string is invalid or NULL, the function returns NULL.

Examples

select hll_union_agg(hll_from_base64(hll_to_base64(pv))), hll_union_agg(pv) from test_hll;

+---------------------------------------------------+-------------------+
| hll_union_agg(hll_from_base64(hll_to_base64(pv))) | hll_union_agg(pv) |
+---------------------------------------------------+-------------------+
|                                                 3 |                 3 |
+---------------------------------------------------+-------------------+

select hll_cardinality(hll_from_base64(hll_to_base64(hll_hash('abc'))));

+------------------------------------------------------------------+
| hll_cardinality(hll_from_base64(hll_to_base64(hll_hash('abc')))) |
+------------------------------------------------------------------+
|                                                                1 |
+------------------------------------------------------------------+

select hll_cardinality(hll_from_base64(hll_to_base64(hll_hash(''))));

+---------------------------------------------------------------+
| hll_cardinality(hll_from_base64(hll_to_base64(hll_hash('')))) |
+---------------------------------------------------------------+
|                                                             1 |
+---------------------------------------------------------------+

select hll_cardinality(hll_from_base64(hll_to_base64(hll_hash(NULL))));

+-----------------------------------------------------------------+
| hll_cardinality(hll_from_base64(hll_to_base64(hll_hash(NULL)))) |
+-----------------------------------------------------------------+
|                                                               0 |
+-----------------------------------------------------------------+