mysql-hll:用于 MySQL 的 HyperLogLog UDF

用于 MySQL 的 HyperLogLog UDF 例子 增量积累 CREATE TABLE ` uniqueUsersPerDay `( ` day ` DATE PRIMARY KEY , ` hll ` BLOB); SET @bits = 14 ; -- set storage size to 2^@bits bytes (standard error 0.81%) SET @userId = 1 ; INSERT INTO ` uniqueUsersPerDay ` ( ` day ` , ` hll ` ) VALUES (CURDATE(), HLL_CREATE(@bits, @userId)) ON DUPLICATE KEY UPDATE ` hll ` = HLL_ADD( ` hll ` , @userId) ; SET @userId = 2 ; INS