How can I use substr function in query or find an alternative way

[jiawei chen]

Hi kylin's developers,
    I am using kylin-1.6.0 now. I have to use a sql query like:

SELECT
SUBSTR(TO_CHAR(`time`,'YYYYMMDDHH24MISS'),9,2) AS PERIOD,
COUNT(*) AS LL,
FROM table_name
GROUP BY
SUBSTR(TO_CHAR(`time`,'YYYYMMDDHH24MISS'),9,2);

and I got a failed response that shows no match found for function
signature TO_CHAR, (If I remove to_char, SUBSTR still not found).

Is there any plane to support these transform functions?
Or what alternative way can I choose?

Thank you!