How to select or get data of a column delimited by comma in sql server

Suppose we have KeyValue like this:

Id	Key	Value
1	Name	Scott
2	Age	42
3	DOJ	12/05/2011
4	IsActive	1

We want to write a sql query which will return data of column key delimited by comma or any other character like this:

CSV

Name,Age,DOJ,IsActive

Sql server query:

DECLARE @SqlQuery AS VARCHAR(MAX) = ''

SELECT @SqlQuery = @SqlQuery + [KEY] + ',' FROM KeyValue

SELECT LEFT(@SqlQuery,LEN(@SqlQuery)-1)