Updating with Incremental Values
Some applications do not update a data set by overwriting values in the master data set with new values from a transaction data set. Instead, they update a variable by mathematically manipulating its value based on the value of a variable in the transaction data set.
In this example, a bookstore uses SAS to keep track of weekly sales and year-to-date sales. The program that follows creates, sorts by Title, and displays the data set, YEAR_SALES, which contains the year-to-date information.
data year_sales;input Title $ 1-25 Author $ 27-50 Sales; datalines; The Milagro Beanfield War Nichols, John 303 The Stranger Camus, Albert 150 Always Coming Home LeGuin, Ursula 79 Falling through Space Gilchrist, Ellen 128 ...