Removes PlainSelect casting in JSqlParserQueryEnhancer.

Closes: #3869
Original pull request: #3870

Signed-off-by: Diego Pedregal <[email protected]>

Author: thmasker

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

@@ -66,6 +66,7 @@
  * @author Geoffrey Deremetz
  * @author Yanming Zhou
  * @author Christoph Strobl
+ * @author Diego Pedregal
  * @since 2.7.0
  */
 public class JSqlParserQueryEnhancer implements QueryEnhancer {
@@ -241,7 +242,7 @@ private static String detectProjection(Statement statement) {
 		}
 
 		StringJoiner joiner = new StringJoiner(", ");
-		for (SelectItem<?> selectItem : ((PlainSelect) selectBody).getSelectItems()) {
+		for (SelectItem<?> selectItem : selectBody.getPlainSelect().getSelectItems()) {
 			joiner.add(selectItem.toString());
 		}
 		return joiner.toString().trim();

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

@@ -263,4 +263,13 @@ private static DefaultQueryRewriteInformation getRewriteInformation(Sort sort) {
 				ReturnedType.of(Object.class, Object.class, new SpelAwareProxyProjectionFactory()));
 	}
 
+	@Test // GH-3869
+	void shouldWorkWithoutFromClause() {
+		String query = "SELECT is_contained_in(:innerId, :outerId)";
+
+		StringQuery stringQuery = new StringQuery(query, true);
+
+		assertThat(stringQuery.getQueryString()).isEqualTo(query);
+	}
+
 }