Handle subqueries when used inside HQL INSERT statements.

Potentialy subqueries can crop up inside INSERT statements. We need to handle this as well.

NOTE: INSERT statements aren't defined in JPQL, so this problem doesn't overlap with standard JPA queries.

See #2977

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/HqlQueryTransformer.java

@@ -96,6 +96,8 @@ class HqlQueryTransformer extends HqlQueryRenderer {
 			return true;
 		} else if (ctx instanceof HqlParser.SelectStatementContext) {
 			return false;
+		} else if (ctx instanceof HqlParser.InsertStatementContext) {
+			return false;
 		} else {
 			return isSubquery(ctx.getParent());
 		}

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/HqlQueryTransformerTests.java

@@ -973,6 +973,19 @@ class HqlQueryTransformerTests {
 				.isEqualTo("FROM Story WHERE enabled = true order by created desc");
 	}
 
+	@Test // GH-2977
+	void isSubqueryThrowsException() {
+
+		String query = """
+				insert into MyEntity (id, col)
+				select max(id), col
+				from MyEntityStaging
+				group by col
+				""";
+
+		assertThat(createQueryFor(query, Sort.unsorted())).isEqualToIgnoringWhitespace(query);
+	}
+
 	private void assertCountQuery(String originalQuery, String countQuery) {
 		assertThat(createCountQueryFor(originalQuery)).isEqualTo(countQuery);
 	}