Question

I want to compute scores for some data I have in a MySQL database. The score will be computed as follows:

score = COUNT(purchases MADE BETWEEN NOW() AND (NOW() - 1 WEEK))
  + 0.7 * COUNT(purchases MADE BETWEEN (NOW() - 1 WEEK) AND (NOW() - 2 WEEKS))
  + 0.4 * COUNT(purchases OLDER THAN (NOW() - 2 WEEKS))

I have purchses in a table with a purchase_time column.

Is it possible to do this in MySQL and get output similar to the following?

ORDER_ID    SCORE
   3          8
   4          3
   5          15

Thanks

— EDIT —
The table structure is:

tblOrder - table
id - primary key
created - time stamp

Answer 1

Your between and older need to be converted into CASE.

CASE case_value
    WHEN when_value THEN statement_list
    [WHEN when_value THEN statement_list] ...
    [ELSE statement_list]
END CASE

At the same time you can rewrite the expression so that specific cases are the factors such as

SELECT SUM(
         CASE DATEDIFF(now(),purchase_datetime) DIV 7
           WHEN 0 THEN 1
           WHEN 1 THEN 0.7
           ELSE 0.4
         END
       )
FROM table
WHERE purchase_datetime < now()
GROUP BY ORDER_ID