I have table similar to:

Create Table #test (Letter varchar(5), Products varchar(30))

Insert into #test (Letter, Products)
Values ('A','B,C,D,E,F'),('B','B,C,D,E,F'),('G','B,C,D,E,F'),('Z','B,C,D,E,F'),('E','B,C,D,E,F')

Is it possible to write a CASE expression which will check if the list in the 'Products' column contain a letter from 'Letter' column?