HLL_EMPTY
description
Syntax
HLL_EMPTY(value)
HLL_EMPTY 返回一个 hll 类型的空值。
example
1. MySQL > select hll_cardinality(hll_empty());
2. +------------------------------+
3. | hll_cardinality(hll_empty()) |
4. +------------------------------+
5. | 0 |
6. +------------------------------+
keywords
HLL,HLL_EMPTY
