Made JSqlParserQueryEnhancer aware of MERGE statements.

Closes #2641.

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

@@ -28,6 +28,7 @@ import net.sf.jsqlparser.schema.Column;
 import net.sf.jsqlparser.statement.Statement;
 import net.sf.jsqlparser.statement.delete.Delete;
 import net.sf.jsqlparser.statement.insert.Insert;
+import net.sf.jsqlparser.statement.merge.Merge;
 import net.sf.jsqlparser.statement.select.OrderByElement;
 import net.sf.jsqlparser.statement.select.PlainSelect;
 import net.sf.jsqlparser.statement.select.Select;
@@ -58,6 +59,7 @@ import org.springframework.util.StringUtils;
  *
  * @author Diego Krupitza
  * @author Greg Turnquist
+ * @author Geoffrey Deremetz
  * @since 2.7.0
  */
 public class JSqlParserQueryEnhancer implements QueryEnhancer {
@@ -92,6 +94,8 @@ public class JSqlParserQueryEnhancer implements QueryEnhancer {
 				return ParsedType.DELETE;
 			} else if (statement instanceof Select) {
 				return ParsedType.SELECT;
+			} else if (statement instanceof Merge) {
+				return ParsedType.MERGE;
 			} else {
 				return ParsedType.SELECT;
 			}
@@ -483,10 +487,11 @@ public class JSqlParserQueryEnhancer implements QueryEnhancer {
 	 * <li>{@code ParsedType.UPDATE}: means the top level statement is {@link Update}</li>
 	 * <li>{@code ParsedType.SELECT}: means the top level statement is {@link Select}</li>
 	 * <li>{@code ParsedType.INSERT}: means the top level statement is {@link Insert}</li>
+	 * <li>{@code ParsedType.MERGE}: means the top level statement is {@link Merge}</li>
 	 * </ul>
 	 */
 	enum ParsedType {
-		DELETE, UPDATE, SELECT, INSERT;
+		DELETE, UPDATE, SELECT, INSERT, MERGE;
 	}
 
 }

src/test/java/org/springframework/data/jpa/repository/UserRepositoryTests.java

@@ -107,6 +107,7 @@ import org.springframework.transaction.annotation.Transactional;
  * @author Diego Krupitza
  * @author Daniel Shuy
  * @author Simon Paradies
+ * @author Geoffrey Deremetz
  */
 @ExtendWith(SpringExtension.class)
 @ContextConfiguration("classpath:application-context.xml")
@@ -2810,6 +2811,22 @@ public class UserRepositoryTests {
 				.contains("Gierke", "Arrasz", "Matthews", "raymond", testLastName);
 	}
 
+	@Test // GH-2641
+	void mergeWithNativeStatement() {
+
+		flushTestUsers();
+
+		Optional<User> byIdUser = repository.findById(firstUser.getId());
+		assertThat(byIdUser).isPresent().map(User::getAge).get().isEqualTo(28);
+
+		// when
+		repository.mergeNativeStatement();
+
+		// then
+		Optional<User> afterUpdate = repository.findById(firstUser.getId());
+		assertThat(afterUpdate).isPresent().map(User::getAge).get().isEqualTo(30);
+	}
+
 	private Page<User> executeSpecWithSort(Sort sort) {
 
 		flushTestUsers();

src/test/java/org/springframework/data/jpa/repository/query/QueryEnhancerUnitTests.java

@@ -38,6 +38,7 @@ import org.springframework.data.jpa.domain.JpaSort;
  * Unit tests for {@link QueryEnhancer}.
  *
  * @author Diego Krupitza
+ * @author Geoffrey Deremetz
  */
 class QueryEnhancerUnitTests {
 
@@ -922,6 +923,18 @@ class QueryEnhancerUnitTests {
 		assertThat(queryEnhancer.hasConstructorExpression()).isFalse();
 	}
 
+	@Test // GH-2641
+	void mergeStatementWorksWithJSqlParser() {
+		String query = "merge into a using (select id, value from b) query on (a.id = query.id) when matched then update set a.value = value";
+		StringQuery stringQuery = new StringQuery(query, true);
+		QueryEnhancer queryEnhancer = QueryEnhancerFactory.forQuery(stringQuery);
+
+		assertThat(queryEnhancer.getJoinAliases()).isEmpty();
+		assertThat(queryEnhancer.detectAlias()).isNull();
+		assertThat(queryEnhancer.getProjection()).isEmpty();
+		assertThat(queryEnhancer.hasConstructorExpression()).isFalse();
+	}
+
 	public static Stream<Arguments> insertStatementIsProcessedSameAsDefaultSource() {
 		return Stream.of( //
 				Arguments.of("INSERT INTO FOO(A) VALUES('A')"), //

src/test/java/org/springframework/data/jpa/repository/sample/UserRepository.java

@@ -55,6 +55,7 @@ import org.springframework.transaction.annotation.Transactional;
  * @author Greg Turnquist
  * @author Simon Paradies
  * @author Diego Krupitza
+ * @author Geoffrey Deremetz
  */
 public interface UserRepository
 		extends JpaRepository<User, Integer>, JpaSpecificationExecutor<User>, UserRepositoryCustom {
@@ -693,6 +694,16 @@ public interface UserRepository
 			nativeQuery = true)
 	void insertNewUserWithParamNativeQuery(@Param("lastname") String lastname);
 
+	// GH-2641
+	@Modifying(clearAutomatically = true)
+	@Query(value = "merge into sd_user " + //
+			"using (select id from sd_user where age < 30) request " + //
+			"on (sd_user.id = request.id) " + //
+			"when matched then " + //
+			"    update set sd_user.age = 30", //
+			nativeQuery = true)
+	int mergeNativeStatement();
+
 	interface RolesAndFirstname {
 
 		String getFirstname();