#2147 Fix for ADD: multiple to many outer joins cause wrong count in distinct count…

Copy of Rolands fix in FOCONIS branch. This also brings over some of the extra tests found there.

Note that the SQL is slightly different from the FOCONIS branch in that there is additional foreign key columns included in the sub-query select clause.

ebean-core/src/test/java/org/tests/query/other/TestQuerySingleAttribute.java

@@ -6,16 +6,21 @@ import io.ebean.CountedValue;
 import io.ebean.DB;
 import io.ebean.Ebean;
 import io.ebean.Query;
+import org.junit.After;
+import org.junit.Before;
 import org.junit.Ignore;
 import org.junit.Test;
 import org.tests.inherit.ChildA;
 import org.tests.inherit.Data;
 import org.tests.inherit.EUncle;
+import org.tests.lazyforeignkeys.MainEntity;
+import org.tests.lazyforeignkeys.MainEntityRelation;
 import org.tests.model.basic.Contact;
 import org.tests.model.basic.Customer;
 import org.tests.model.basic.Order;
 import org.tests.model.basic.ResetBasicData;
 import org.tests.model.basic.VwCustomer;
+import org.tests.o2m.OmBasicParent;
 
 import java.sql.Date;
 import java.time.LocalDate;
@@ -24,7 +29,7 @@ import java.util.List;
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class TestQuerySingleAttribute extends BaseTestCase {
-	
+
 	@Test
 	  public void findSingleAttributesTwoToMany() {
 	    ResetBasicData.reset();
@@ -39,7 +44,7 @@ public class TestQuerySingleAttribute extends BaseTestCase {
 		    CountedValue<String> robs0 = (CountedValue<String>) query0.findSingleAttributeList().get(0);
 		    assertThat(robs0.getValue()).isEqualTo("Rob");
 		    assertThat(robs0.getCount()).isEqualTo(1);
-	    
+
 		 // Query with or with equals causing joins
 	    Query<Customer> query = DB.find(Customer.class)
 	        .select("name")
@@ -56,12 +61,13 @@ public class TestQuerySingleAttribute extends BaseTestCase {
 	    assertThat(robs.getValue()).isEqualTo("Rob");
 	    // only one Customer named rob exists, but 7 is returned for the amount of Customers named Rob
 	    assertThat(robs.getCount()).isEqualTo(1);
-	    
-	    // TODO check correct future query
-	    assertThat(sqlOf(query)).contains("select r1.attribute_1, count(*) cnt"
-	        + " from (select t1.id attribute_1 from main_entity_relation t0 left join main_entity t1 on t1.id = t0.id1 ) r1"
-	        + " group by r1.attribute_1"
-	        + " order by count(*) desc, r1.attribute_1");
+
+	    assertThat(sqlOf(query)).contains("select r1.attribute_, count(*) " +
+        "from (select distinct t0.id, t0.name as attribute_ " +
+        "from o_customer t0 left join contact u1 on u1.customer_id = t0.id left join o_order u2 on u2.kcustomer_id = t0.id " +
+        "where t0.name = ? and (u2.status = ? or u1.first_name = ?)) r1 " +
+        "group by r1.attribute_ " +
+        "order by count(*) desc, r1.attribute_");
 	  }
 
   @Test
@@ -142,6 +148,93 @@ public class TestQuerySingleAttribute extends BaseTestCase {
     assertThat(name).isNotNull();
   }
 
+  @Test
+  public void findSingleAttributeList_with_join_column() {
+    ResetBasicData.reset();
+    Query<MainEntityRelation> query = Ebean.find(MainEntityRelation.class)
+      .fetch("entity1", "attr1")
+      .setDistinct(true)
+      .setCountDistinct(CountDistinctOrder.COUNT_DESC_ATTR_ASC)
+      .where().query();
+
+    List<CountedValue<String>> attr1list = query.findSingleAttributeList();
+
+    assertThat(sqlOf(query)).contains("select r1.attribute_, count(*)"
+        + " from (select distinct t0.id, t0.id1, t1.attr1 as attribute_ from main_entity_relation t0 left join main_entity t1 on t1.id = t0.id1) r1"
+        + " group by r1.attribute_"
+        + " order by count(*) desc, r1.attribute_"); // sub-query select clause includes t0.id1
+    assertThat(attr1list).isNotNull();
+    assertThat(attr1list).hasSize(2);
+    assertThat(attr1list.get(0).getValue()).isEqualTo("a1");
+    assertThat(attr1list.get(0).getCount()).isEqualTo(2l);
+    assertThat(attr1list.get(1).getValue()).isEqualTo("a2");
+    assertThat(attr1list.get(1).getCount()).isEqualTo(1l);
+  }
+
+  @Test
+  public void findSingleAttributesVariousSelection1() {
+    Query<MainEntityRelation> query = Ebean.find(MainEntityRelation.class)
+      .fetch("entity1", "attr1")
+      .setCountDistinct(CountDistinctOrder.COUNT_DESC_ATTR_ASC)
+      .where().query();
+    query.findSingleAttributeList();
+    assertThat(sqlOf(query)).contains("select r1.attribute_, count(*)"
+      + " from (select t0.id1, t1.attr1 as attribute_ from main_entity_relation t0 left join main_entity t1 on t1.id = t0.id1) r1"
+      + " group by r1.attribute_"
+      + " order by count(*) desc, r1.attribute_"); // sub-query select clause includes t0.id1
+  }
+
+  @Test
+  public void findSingleAttributesVariousSelection2() {
+    Query<MainEntityRelation> query = Ebean.find(MainEntityRelation.class)
+      .select("attr1")
+      .setCountDistinct(CountDistinctOrder.COUNT_DESC_ATTR_ASC)
+      .where().query();
+    query.findSingleAttributeList();
+    assertThat(sqlOf(query)).contains("select r1.attribute_, count(*)"
+      + " from (select t0.attr1 as attribute_ from main_entity_relation t0) r1"
+      + " group by r1.attribute_"
+      + " order by count(*) desc, r1.attribute_");
+  }
+
+  @Test
+  public void findSingleAttributesVariousSelection3() {
+    Query<MainEntityRelation> query = Ebean.find(MainEntityRelation.class)
+      .select("id")
+      .setCountDistinct(CountDistinctOrder.COUNT_DESC_ATTR_ASC)
+      .where().query();
+    query.findSingleAttributeList();
+    assertThat(sqlOf(query)).contains("select r1.attribute_, count(*)"
+      + " from (select t0.id as attribute_ from main_entity_relation t0) r1"
+      + " group by r1.attribute_"
+      + " order by count(*) desc, r1.attribute_");
+  }
+
+  @Test
+  public void findSingleAttributesVariousSelection4() {
+    Query<MainEntityRelation> query = Ebean.find(MainEntityRelation.class)
+      .fetch("entity1", "id")
+      .setCountDistinct(CountDistinctOrder.COUNT_DESC_ATTR_ASC)
+      .where().query();
+    query.findSingleAttributeList();
+    assertThat(sqlOf(query)).contains("select r1.attribute_, count(*)"
+      + " from (select t0.id1, t1.id as attribute_ from main_entity_relation t0 left join main_entity t1 on t1.id = t0.id1) r1"
+      + " group by r1.attribute_"
+      + " order by count(*) desc, r1.attribute_"); // sub-query select clause includes t0.id1,
+  }
+
+  @Test
+  public void findSingleAttributesVariousSelection5() {
+    Query<OmBasicParent> query = Ebean.find(OmBasicParent.class)
+      .fetch("children", "name")
+      .setCountDistinct(CountDistinctOrder.COUNT_DESC_ATTR_ASC)
+      .where().query();
+    query.findSingleAttributeList();
+    assertThat(sqlOf(query)).contains("select r1.attribute_, count(*)"
+      + " from (select t1.id, t1.name as attribute_ from om_basic_parent t0 left join om_basic_child t1 on t1.parent_id = t0.id) r1 "
+      + "group by r1.attribute_ order by count(*) desc, r1.attribute_"); // sub-query select clause includes t1.id,
+  }
+
   @Test
   public void findSingleAttribute_with_aggregate() {
 
@@ -664,4 +757,43 @@ public class TestQuerySingleAttribute extends BaseTestCase {
       System.out.println(" count:" + entry.getCount()+" orderStatus:" + entry.getValue() );
     }
   }
+
+  @Before
+  public void setup() {
+    MainEntity e1 = new MainEntity();
+    e1.setId("1");
+    e1.setAttr1("a1");
+    DB.save(e1);
+
+    MainEntity e2 = new MainEntity();
+    e2.setId("2");
+    e2.setAttr1("a2");
+    DB.save(e2);
+
+    MainEntity e3 = new MainEntity();
+    e3.setId("3");
+    e3.setAttr1("a1");
+    DB.save(e3);
+
+    MainEntityRelation rel = new MainEntityRelation();
+    rel.setEntity1(e1);
+    rel.setEntity2(e1);
+    DB.save(rel);
+
+    rel = new MainEntityRelation();
+    rel.setEntity1(e2);
+    rel.setEntity2(e2);
+    DB.save(rel);
+
+    rel = new MainEntityRelation();
+    rel.setEntity1(e3);
+    rel.setEntity2(e3);
+    DB.save(rel);
+  }
+
+  @After
+  public void cleanup() {
+    Ebean.find(MainEntityRelation.class).delete();
+    Ebean.find(MainEntity.class).delete();
+  }
 }