How to write a query with a date?

Question

SQL Server

How to write a request with a date correctly (I can’t write it correctly because I can’t understand)
"Display the number of new products in the store - products that were delivered during the last week (7 days)" I
did this:

SELECT COUNT(Product.idProduct) FROM Product WHERE Product.idProduct IN
 (SELECT Dalivery.idProduct FROM Dalivery 
WHERE (YEAR(Dalivery.DateDelivery) BETWEEN YEAR(DATE_ADD(GETDATE(), INTERVAL -7 DAY)) AND GETDATE() ) );

And I'm doing something wrong. I did n't find an
explanation for working with dates .

Answer 1

stupidly difference in days between date and "today":
the difference is less than or equal to 7 - for the last 7 days
, but if a "hit" in a calendar week is required, the expression will be somewhat more poignant

Answer 2

A small FAQ on working with dates.