fix xref

Author: JPryce-Aklundh

modules/ROOT/pages/subqueries/call-subquery.adoc

@@ -573,7 +573,7 @@ RETURN
 [[call-post-union]]
 == Post-union processing
 
-Call subqueries can be used to further process the results of a xref:queries/composed-queries/combined-queries.adoc[`UNION`] query.
+Call subqueries can be used to further process the results of a xref:queries/combined-queries.adoc[`UNION`] query.
 
 .Using `UNION` within a `CALL` subquery
 ====