Unable to implement function in group by clause

Hi scylla team,
Can anyone help me with following issue:

I am required to execute the following query, but was not able to execute. Seems like we can’t use function in group by clause.

Can anyone help me to confirm weather we can use function in group clause or not.

select user_id, toDate(time_field) as period_start_date, sum(add_cash_amt)
from t
where user_id = 1234
group by user_id, toDate(time_field)
ALLOW FILTERING;

Can you post the error?
How the table is defined?
Why are you using ALLOW FILTERING? Maybe you want to group by a column that doesn’t belong to the partition key, which is not possible, per doc: " Using the GROUP BY option, it is only possible to group rows at the partition key level or at a clustering column level"
Also, you’re repeating the toDate function call in the group by clause.