stata command for standard deviation using different groups

[lex man]

Hi, this is my firs message so i apologize for any mistakes i make.

I have a dataset of three variables: countries, dates, and y. initially, i created three dummy variables in order to divide the countries into specific groups such as europe, asia etc with the dummy being equal to 1 if the country is part of europe etc. my problem is that i want to find the standard deviation of Y for each year in each group. so for year 1 i want to use the y values of european countries and find their standard deviation. then the same for year 2, 3, etc.
do you have any command in mind? thank you in advance