Add amounts in a column based on transaction date in another column
 

I have a spreadsheet with 6 columns Customer No, Name, Amt, Date, By and
Note. It could have as many as 5,000 rows.
What I want to be able to do is have a cell that displays the total
transaction amounts for the current day (all transactions done today) and
another cell that dispalys the total amount transactions for Yesterday (day
before today.)
I'd also like to be able to input a date and get the total transaction
amount for any given date.
Date column is D and Amount column is C.

I know this isn't too dificult but my programming skills arent the
greatest. I appreciate any help you can give me.

Jon