Hi,
In a table, you can first group rows using unique date values in the Date column, then compute your required statistics using accumarray. You can refer to the example below:
dates = T.Date;
[uniqueDates,ua,uc] = unique(dates);
mean_T = accumarray(uc,T.Volumn,[],@mean);
new_table = table(uniqueDates,mean_T);
You can replace @mean with your function to compute average first decile. Refer prctile for the same.
