Copy data from one existing row to another existin

Question

I have a table full of tracking data for as specific course, course number 6.

Now I have added new tracking data for course number 11.

Each row of data is for one user for one course, so for users assigned to both course 6 and course 11 there are two rows of data.

The client wants all users who have completed course number 6 any time after August 1st 2008 to also have completion marked for course 11. However I can't just convert the 6 to 11 because they want to preserve their old data for course 6.

So for every row that has a course number of 6, is marked as complete, and is greater than the date August 1st 2008, I want to write the completion data over the row that contains the tracking for course 11 for that specific user.

I would need to carry over the data from the course 6 row to the course 11 row so things like user score and date of posted completion is moved over.

Here is the structure of the table:

userID (int)
courseID (int)
course (bit)
bookmark (varchar(100))
course_date (datetime)
posttest (bit)
post_attempts (int)
post_score (float)
post_date (datetime)
complete (bit)
complete_date (datetime)
exempted (bit)
exempted_date (datetime)
exempted_reason (int)
emailSent (bit)

Some values will be NULL and userID/courseID obviously won't be carried over as that is already in the right place.

Answer 1

UPDATE c11
SET
    c11.completed= c6.completed,
    c11.complete_date = c6.complete_date,
-- rest of columns to be copied
FROM courses c11 inner join courses c6 on
    c11.userID = c6.userID 
    and c11.courseID = 11 and c6.courseID = 6
     -- and any other checks

I have always viewed the From clause of an update, like one of a normal select. Actually if you want to check what will be updated before running the update, you can take replace the update parts with a select c11.*. See my comments on the lame duck's answer.