创建函数报ERROR 1418 (HY000)

mysql> use test;
Database changed
mysql> delimiter //
mysql> CREATE FUNCTION hello (s CHAR(20)) RETURNS CHAR(50) 
    -> RETURN CONCAT('Hello, ',s,'!');
    -> //
ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable)

mysql> SET GLOBAL log_bin_trust_function_creators = 1;
    -> //
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE FUNCTION hello (s CHAR(20)) RETURNS CHAR(50) 
    -> RETURN CONCAT('Hello, ',s,'!');
    -> //
Query OK, 0 rows affected (0.00 sec)

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