From c1a479e1f467fa1a38434d7e16a1df78b7d5a6af Mon Sep 17 00:00:00 2001
From: rob bygrave <robin.bygrave@gmail.com>
Date: Wed, 24 Oct 2018 23:26:19 +1300
Subject: [PATCH] #1512 - Invalid SQL with Postgres + order by nulls first/last
 + where() expression on ManyToMany

---
 .../server/query/SqlTreeBuilderTest.java      | 37 ++++++++++---------
 .../orderby/TestOrderByWithDistinct.java      | 21 +++++++++++
 2 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/src/test/java/io/ebeaninternal/server/query/SqlTreeBuilderTest.java b/src/test/java/io/ebeaninternal/server/query/SqlTreeBuilderTest.java
index 7b8232ba6..2c5beb403 100644
--- a/src/test/java/io/ebeaninternal/server/query/SqlTreeBuilderTest.java
+++ b/src/test/java/io/ebeaninternal/server/query/SqlTreeBuilderTest.java
@@ -7,57 +7,58 @@ import static org.junit.Assert.*;
 public class SqlTreeBuilderTest {
 
   @Test
-  public void mergeOnDistinct_equal() throws Exception {
-
+  public void mergeOnDistinct_equal() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.id"), "t0.id");
   }
 
   @Test
-  public void mergeOnDistinct_add() throws Exception {
-
+  public void mergeOnDistinct_add() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre"), "t0.cre, t0.id");
   }
 
   @Test
-  public void mergeOnDistinct_contained() throws Exception {
-
+  public void mergeOnDistinct_contained() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre, t0.id"), "t0.cre, t0.id");
   }
 
   @Test
-  public void mergeOnDistinct_overlap() throws Exception {
-
+  public void mergeOnDistinct_overlap() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id, t1.id", "t0.cre, t0.id"), "t0.cre, t0.id, t1.id");
   }
 
   @Test
-  public void mergeOnDistinct_overlapBoth() throws Exception {
-
+  public void mergeOnDistinct_overlapBoth() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id, t1.id", "t0.cre, t1.id, t0.id"), "t0.cre, t1.id, t0.id");
   }
 
   @Test
-  public void mergeOnDistinct_inlineAscDesc() throws Exception {
-
+  public void mergeOnDistinct_inlineAscDesc() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre asc, t1.bb desc, t3.b"), "t0.cre, t1.bb, t3.b, t0.id");
   }
 
   @Test
-  public void mergeOnDistinct_inlineAscDesc2() throws Exception {
-
+  public void mergeOnDistinct_inlineAscDesc2() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre desc, t1.bb asc, t3.b"), "t0.cre, t1.bb, t3.b, t0.id");
   }
 
   @Test
-  public void mergeOnDistinct_trailingAsc() throws Exception {
-
+  public void mergeOnDistinct_trailingAsc() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre asc"), "t0.cre, t0.id");
   }
 
   @Test
-  public void mergeOnDistinct_trailingDesc() throws Exception {
-
+  public void mergeOnDistinct_trailingDesc() {
     assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre desc"), "t0.cre, t0.id");
   }
 
+  @Test
+  public void mergeOnDistinct_trailingDescNullsFirst() {
+    assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre desc nulls first"), "t0.cre, t0.id");
+  }
+
+  @Test
+  public void mergeOnDistinct_trailingDescNullsLast() {
+    assertEquals(SqlTreeBuilder.mergeOnDistinct("t0.id", "t0.cre desc nulls last"), "t0.cre, t0.id");
+  }
+
 }
diff --git a/src/test/java/org/tests/query/orderby/TestOrderByWithDistinct.java b/src/test/java/org/tests/query/orderby/TestOrderByWithDistinct.java
index 2090a0566..9d2ece465 100644
--- a/src/test/java/org/tests/query/orderby/TestOrderByWithDistinct.java
+++ b/src/test/java/org/tests/query/orderby/TestOrderByWithDistinct.java
@@ -37,6 +37,27 @@ public class TestOrderByWithDistinct extends BaseTestCase {
 
   }
 
+  @Test
+  public void testDistinctOn() {
+
+    MRole role = Ebean.getReference(MRole.class, 1);
+
+    Query<MUser> query = Ebean.find(MUser.class)
+      .where()
+      .eq("roles", role)
+      .orderBy("userName asc nulls first");
+
+    query.findList();
+
+    String sql = sqlOf(query);
+    if (isPostgres()) {
+      assertThat(sql).contains("select distinct on (t0.user_name, t0.userid) t0.userid,");
+    } else if (isH2()) {
+      assertThat(sql).contains("select distinct t0.userid, t0.user_name, t0.user_type_id,");
+    }
+
+  }
+
 
   @Test
   public void testOrderByWithDistinct() {