更新时间:2024-01-31 GMT+08:00
HLL操作符
HLL类型支持如下操作符:
表1 HLL操作符
HLL操作符 |
描述 |
返回值类型 |
示例 |
= |
比较hll或hll_hashval的值是否相等。 |
bool |
|
SELECT (hll_empty() || hll_hash_integer(1)) = (hll_empty() || hll_hash_integer(1));
?column?
----------
t
(1 row)
|
|
SELECT hll_hash_integer(1) = hll_hash_integer(1);
?column?
----------
t
(1 row)
|
|
<> or != |
比较hll或hll_hashval是否不相等。 |
bool |
|
SELECT (hll_empty() || hll_hash_integer(1)) <> (hll_empty() || hll_hash_integer(2));
?column?
----------
t
(1 row)
|
|
SELECT hll_hash_integer(1) <> hll_hash_integer(2);
?column?
----------
t
(1 row)
|
|
|| |
可代表hll_add, hll_union, hll_add_rev三个函数的功能。 |
hll |
|
SELECT hll_empty() || hll_hash_integer(1);
?column?
--------------------------
\x128b7f8895a3f5af28cafe
(1 row)
|
|
SELECT hll_hash_integer(1) || hll_empty();
?column?
--------------------------
\x128b7f8895a3f5af28cafe
(1 row)
|
|
SELECT (hll_empty() || hll_hash_integer(1)) || (hll_empty() || hll_hash_integer(2));
?column?
------------------------------------------
\x128b7f8895a3f5af28cafeda0ce907e4355b60
(1 row)
|
|
# |
计算出hll的Dintinct值, 同hll_cardinality函数。 |
integer |
|
SELECT #(hll_empty() || hll_hash_integer(1));
?column?
----------
1
(1 row)
|
|