# 操作符
#### =
描述：比较hll或hll_hashval的值是否相等。
返回值类型：bool
示例：
```
--hll
gaussdb=# SELECT (hll_empty() || hll_hash_integer(1)) = (hll_empty() || hll_hash_integer(1));
column 
----------
 t
(1 row)
--hll_hashval
gaussdb=# SELECT hll_hash_integer(1) = hll_hash_integer(1);
 ?column? 
----------
 t
(1 row)
```
#### \<\> or !=
描述：比较hll或hll_hashval是否不相等。
返回值类型：bool
示例：
```
--hll
gaussdb=# SELECT (hll_empty() || hll_hash_integer(1)) <> (hll_empty() || hll_hash_integer(2));
 ?column? 
----------
 t
(1 row)
--hll_hashval
gaussdb=# SELECT hll_hash_integer(1) <> hll_hash_integer(2);
 ?column? 
----------
 t
(1 row)
```
#### \|\|
描述：可代表hll_add, hll_union, hll_add_rev三个函数的功能。
返回值类型：hll
示例：
```
--hll_add
gaussdb=# SELECT hll_empty() || hll_hash_integer(1);
                                  ?column?
----------------------------------------------------------------------------
 \x484c4c08000002002b0900000000000000f03f3e2921ff133fbaed3e2921ff133fbaed00
(1 row)
--hll_add_rev
gaussdb=# SELECT hll_hash_integer(1) || hll_empty();
                                  ?column?
----------------------------------------------------------------------------
 \x484c4c08000002002b0900000000000000f03f3e2921ff133fbaed3e2921ff133fbaed00
(1 row)
--hll_union
gaussdb=# SELECT (hll_empty() || hll_hash_integer(1)) || (hll_empty() || hll_hash_integer(2));
                                          ?column?
--------------------------------------------------------------------------------------------
 \x484c4c10002000002b090000000000000000400000000000000000b3ccc49320cca1ae3e2921ff133fbaed00
(1 row)
```
#### #
描述：计算出hll的distinct值，同hll_cardinality函数。
返回值类型：int
示例：
```
gaussdb=# SELECT #(hll_empty() || hll_hash_integer(1));
 ?column? 
----------
        1
(1 row)
```