Add graph.propertiesByName query example that selects subset of graphs (#555)

#543

Author: smietana

modules/ROOT/pages/functions/graph.adoc

@@ -89,6 +89,22 @@ Properties for all graphs on the current composite database are returned.
 
 |===
 
+.Query
+[source, cypher, indent=0]
+----
+UNWIND graph.names() AS name
+WITH name, graph.propertiesByName(name) AS props
+WHERE "A" IN props.tags
+CALL {
+  USE graph.byName(name)
+  MATCH (n)
+  RETURN n
+}
+RETURN n
+----
+
+Returns all nodes from a subset of graphs that have a `tags` property containing `"A"`.
+
 ======
 
 [[functions-graph-byname]]