建表时定义 global partition index 报错

create table T1 (
a int,
b int,
c int,
CONSTRAINT pk_a PRIMARY KEY (`a`),
KEY `index_b` (`b`) GLOBAL partition by key(`b`) partitions 128);

ErrorCode = 1064, SQLState = 42000, Details = You have an error in your SQL syntax; check the manual that corresponds to your OceanBase version for the right syntax to use near 'partition by key(`b`) partitions 128 at line 1

create index `index_xxxx` (`xxxx`) global partition by key(`xxxx`) partitions 128;