HLL_EMPTY
description
Syntax
HLL_EMPTY(value)
HLL_EMPTY 返回一个 hll 类型的空值。
example
MySQL > select hll_cardinality(hll_empty());
+------------------------------+
| hll_cardinality(hll_empty()) |
+------------------------------+
| 0 |
+------------------------------+keywords
HLL,HLL_EMPTY