How to update data in cnosdb？

Question

I created a table and wrote some data. Now I want to change the value of ta column using Update statement.

create table test(fa bigint, tags(ta));
insert into table test(ta, fa) values ('ta', 1);

select * from test;
+-------------------------------+----+----+
| time                          | ta | fa |
+-------------------------------+----+----+
| 1970-01-01T00:00:00.000000001 | ta | 1  |
+-------------------------------+----+----+

I try:

update test set ta = 'test_ta'
where time = timestamp '1970-01-01T00:00:00.000000001' and ta = 'ta';

But it didn't succeed

I didn't find CnosDB's description about the Update statement.

I want to know a way to change data.