Added example

Author: JoelBergstrand

modules/ROOT/pages/errors/gql-errors/42I64.adoc

@@ -1,7 +1,33 @@
 = 42I64
 
 == Status description
-error: syntax error or access rule violation - unsupported aggregation. `{ <<msg>> }` currently not supported after NEXT `{ <<context>> }`.
+error: syntax error or access rule violation - unsupported aggregation. { <<msg>> } currently not supported after `NEXT` { <<context>> }.
+
+== Example scenario
+
+For example, when aggregating in a `UNION` query after a `NEXT`:
+
+[source,cypher]
+----
+UNWIND [1, 2] AS x
+RETURN x
+
+NEXT
+
+RETURN COUNT(x)
+UNION ALL
+RETURN COUNT(x)
+----
+
+You will receive an error with GQLSTATUS xref:errors/gql-errors/42001.adoc[42001].
+This error has a cause detailed in xref:errors/gql-errors/42I64.adoc[42I64] and status description:
+
+
+[source]
+----
+error: syntax error or access rule violation - unsupported aggregation. Aggregations are currently not supported in `NEXT` when used in a `UNION`.
+----
+
 
 ifndef::backend-pdf[]
 [discrete.glossary]

modules/ROOT/pages/errors/gql-errors/index.adoc

@@ -1036,7 +1036,7 @@ Status description:: error: syntax error or access rule violation - unsupported
 
 === xref:errors/gql-errors/42I64.adoc[42I64]
 
-Status description:: error: syntax error or access rule violation - unsupported aggregation. `{ <<msg>> }` currently not supported in NEXT `{ <<context>> }`.
+Status description:: error: syntax error or access rule violation - unsupported aggregation. { <<msg>> } currently not supported in `NEXT` { <<context>> }.
 
 [role=label--changed-2025.03]
 === xref:errors/gql-errors/42N00.adoc[42N00]