Sum quarterly rows into annual results of revenue

Answer 1

[Akira Agata]

How about the following?

% Create data table with same structure of yours
Date = repelem(datetime(2017,3,1)+3*calmonths(0:3),1,3)';
Code = repmat(categorical({'abc','def','ghi'}),1,4)';
Quantity = randi(100,12,1);
Price = randi(10,12,1)/10;
T = table(Date,Code,Quantity,Price);

% Calculate yearly revenue for each code
group = findgroups(T.Code);
Revenue =...
  splitapply(@(x,y) sum(x.*y),T.Quantity,T.Price,group);