达梦数据库是支持TIMESTAMP(6)字段类型的，

测试过程如下：
create table test_date(C1 TIMESTAMP(6));
INSERT INTO test_date VALUES(TIMESTAMP ‘2022-10-11 09:10:21’);
INSERT INTO test_date VALUES(TIMESTAMP ‘2022-10-11 10:10:21’);
INSERT INTO test_date VALUES(TIMESTAMP ‘2022-10-11 11:10:21’);
INSERT INTO test_date VALUES(TIMESTAMP ‘2022-10-11 12:10:21’);
commit;
select date_format(C1,‘%Y-%m-%d %H:%i:%s.%f’) from test_date;

SQL> select date_format(C1,‘%Y-%m-%d %H:%i:%s.%f’) from test_date;

行号 DATE_FORMAT(C1,‘%Y-%m-%d%H:%i:%s.%f’)

1 2022-10-11 09:10:21.000000
2 2022-10-11 10:10:21.000000
3 2022-10-11 11:10:21.000000
4 2022-10-11 12:10:21.000000

已用时间: 0.832(毫秒). 执行号:2310.
SQL>