SQL Replace blank value in case statement

SQL Replace blank value in case statement

I have two tables:
Student (ks2en, ks2ma, ks2av)
Subject (name)
I have the following conditional statement which depending on the subject
lists the values in the student columns. These are then subsequently
grouped by their respective student column.
In any combination I would like to replace '' blank values in the result
set with 'No KS2'.
Here is my case statement which conditionally selects the appropriate
column from the student table base on the subject name in the subject
table.
CASE
WHEN COALESCE(Name, '') = 'English' THEN
[Ks2en]
WHEN COALESCE(Name, '') = 'Mathematics' THEN
[Ks2ma]
ELSE
[Ks2av]
END AS KS2
Example data:
ks2en
2a
2a
3a
4c
5a
3a
2a
1c
When the subject name is 'English' then the following results are displayed:
KS2
No KS2
1c
2a
3a
4c
5a
Just to be clear, don't worry about ordering, grouping or the conditional
element of the statement as I have got these all working. It's just
replacing blank values with 'No KS2' so that it displays as one of the
groups of values in the results set as above.