Am trying to display only unique values from a matrix column
Is it possible with using the Query module?
Well, the query module gives you direct access to SQL querying your database tables, so this seem quite possible. It depends on the complexity: Are you looking to isolate rows based on a unique column? Isolate entirely unique rows? We'd need more details to help better.
But, without more info, a good start is learning about the
DISTINCT clause available in MySQL queries: http://www.mysqltutorial.org/mysql-distinct.aspx