更新时间:2025-05-29 GMT+08:00
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:
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--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:
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--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:
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--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:
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gaussdb=# SELECT #(hll_empty() || hll_hash_integer(1)); ?column? ---------- 1 (1 row) |
父主题: HLL函数和操作符