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Version: Candidate-3.3

hll_union

Description

Returns the concatenation of a set of HLL values.

Syntax

hll_union(hll)

Examples

mysql> select k1, hll_cardinality(hll_union(v1)) from tbl group by k1;
+------+----------------------------------+
| k1 | hll_cardinality(hll_union(`v1`)) |
+------+----------------------------------+
| 2 | 4 |
| 1 | 3 |
+------+----------------------------------+