Help on Set Analysis Variable Usage

[#1]

I have an expression

=Count({<Question_No={'Q8'},AnswerID={2},CS_Survey={'Post Sales Follow-Up Feedback'}>}Customer)

same I am trying to achieve by using variable, but not getting the proper output

=Count({<Question_No={'Q8'},AnswerID={2},CS_Survey={$(vSales)}>}Customer)

Pls suggest the correct one..

Thanks..

[#2 · Accepted solution]

I found the mistake, this can be achieved by using
=Count({<Question_No={'Q8'},AnswerID={2},CS_Survey={"$(vSales)"}>}Customer)