This paper presents Logos, a system that provides natural language translations for relational queries expressed in SQL. Our translation mechanism is based on a graph-based approach to the query translation problem. We represent various forms of structured queries as directed graphs and we annotate the graph edges with template labels using an extensible template mechanism. Logos uses different graph traversal strategies for efficiently exploring these graphs and composing textual query descriptions. The audience may interactively explore Logos using various database schemata and issuing either sample or ad hoc queries. © 2012 ACM.