HHH-16697 Fix auto type discovery for aggregate functions on Oracle

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/OracleLegacyDialect.java

@@ -715,7 +715,7 @@ public class OracleLegacyDialect extends Dialect {
 				}
 				//intentional fall-through:
 			case Types.DECIMAL:
-				if ( scale == 0 ) {
+				if ( scale == 0 && precision != 0 ) {
 					// Don't infer TINYINT or SMALLINT on Oracle, since the
 					// range of values of a NUMBER(3,0) or NUMBER(5,0) just
 					// doesn't really match naturally.

hibernate-core/src/main/java/org/hibernate/dialect/OracleDialect.java

@@ -767,7 +767,7 @@ public class OracleDialect extends Dialect {
 				}
 				//intentional fall-through:
 			case DECIMAL:
-				if ( scale == 0 ) {
+				if ( scale == 0 && precision != 0 ) {
 					// Don't infer TINYINT or SMALLINT on Oracle, since the
 					// range of values of a NUMBER(3,0) or NUMBER(5,0) just
 					// doesn't really match naturally.

hibernate-core/src/test/java/org/hibernate/orm/test/procedure/OracleStoredProcedureTest.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.orm.test.procedure;
 
+import java.math.BigDecimal;
 import java.sql.CallableStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -187,11 +188,11 @@ public class OracleStoredProcedureTest {
 	public void testStoredProcedureReturnValue(EntityManagerFactoryScope scope) {
 		scope.inTransaction(
 				entityManager -> {
-					Integer phoneCount = (Integer) entityManager
+					BigDecimal phoneCount = (BigDecimal) entityManager
 							.createNativeQuery( "SELECT fn_count_phones(:personId) FROM DUAL" )
 							.setParameter( "personId", person1.getId() )
 							.getSingleResult();
-					assertEquals( 2, phoneCount );
+					assertEquals( BigDecimal.valueOf( 2 ), phoneCount );
 				}
 		);
 	}

hibernate-core/src/test/java/org/hibernate/orm/test/sql/OracleStoredProcedureTest.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.orm.test.sql;
 
+import java.math.BigDecimal;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.time.LocalDateTime;
@@ -227,11 +228,11 @@ public class OracleStoredProcedureTest {
     @Test
     public void testStoredProcedureReturnValue(EntityManagerFactoryScope scope) {
         scope.inTransaction( entityManager -> {
-            Integer phoneCount = (Integer) entityManager
+            BigDecimal phoneCount = (BigDecimal) entityManager
                     .createNativeQuery( "SELECT fn_count_phones(:personId) FROM DUAL" )
                     .setParameter( "personId", 1 )
                     .getSingleResult();
-            assertEquals( 2, phoneCount );
+            assertEquals( BigDecimal.valueOf( 2L ), phoneCount );
         } );
     }
 }

hibernate-core/src/test/java/org/hibernate/orm/test/sql/autodiscovery/AutoDiscoveryTest.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.orm.test.sql.autodiscovery;
 
+import java.math.BigDecimal;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
@@ -20,6 +21,7 @@ import org.hibernate.engine.spi.SessionImplementor;
 import org.hibernate.jdbc.Work;
 
 import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.hibernate.testing.orm.junit.JiraKey;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -137,4 +139,23 @@ public class AutoDiscoveryTest extends BaseCoreFunctionalTestCase {
 		session.getTransaction().commit();
 		session.close();
 	}
+
+	@Test
+	@JiraKey( "HHH-16697" )
+	public void testAggregateQueryAutoDiscovery() {
+		Session session = openSession();
+		session.beginTransaction();
+		User u = new User( "steve" );
+		session.persist( u );
+		session.getTransaction().commit();
+		session.close();
+
+		session = openSession();
+		session.beginTransaction();
+		List<Object> result = session.createNativeQuery( "select sum(39.74) from t_user u" ).list();
+		Assert.assertEquals( new BigDecimal( "39.74" ), result.get( 0 ) );
+		session.remove( u );
+		session.getTransaction().commit();
+		session.close();
+	}
 }