Add support for ordering by column index

Author: mythz

lib/ServiceStack.Client.dll

@@ -509,6 +509,11 @@ public virtual SqlExpression<T> OrderBy(string orderBy)
             return UnsafeOrderBy(orderBy.SqlVerifyFragment());
         }
 
+        public virtual SqlExpression<T> OrderBy(long columnIndex)
+        {
+            return UnsafeOrderBy(columnIndex.ToString());
+        }
+
         public virtual SqlExpression<T> UnsafeOrderBy(string orderBy)
         {
             orderByProperties.Clear();
@@ -692,9 +697,18 @@ private SqlExpression<T> OrderByDescendingInternal(Expression keySelector)
         }
 
         public virtual SqlExpression<T> OrderByDescending(string orderBy)
+        {
+            return UnsafeOrderByDescending(orderBy.SqlVerifyFragment());
+        }
+
+        public virtual SqlExpression<T> OrderByDescending(long columnIndex)
+        {
+            return UnsafeOrderByDescending(columnIndex.ToString());
+        }
+
+        private SqlExpression<T> UnsafeOrderByDescending(string orderBy)
         {
             orderByProperties.Clear();
-            orderBy.SqlVerifyFragment();
             orderByProperties.Add(orderBy + " DESC");
             BuildOrderByClauseInternal();
             return this;

lib/ServiceStack.Common.dll

@@ -139,8 +139,10 @@
     <Compile Include="Legacy\ApiSqlServerLegacyTests.cs" />
     <Compile Include="SchemaTests.cs" />
     <Compile Include="SelectParamTests.cs" />
+    <Compile Include="Support\ArtistTrackTestBase.cs" />
     <Compile Include="Support\JoinSqlBuilder.cs" />
     <Compile Include="TemporaryNamingStrategy.cs" />
+    <Compile Include="UseCase\ArtistTrackSqlExpressions.cs" />
     <Compile Include="UseCase\ExpressionsAuthorTests.cs" />
     <Compile Include="Expression\ComplexJoinTests.cs" />
     <Compile Include="Expression\ExpressionUsingCustomSerializedEnumTests.cs" />

src/ServiceStack.OrmLite/Expressions/SqlExpression.cs

@@ -0,0 +1,69 @@
+using System.Collections.Generic;
+using System.Data;
+using ServiceStack.DataAnnotations;
+
+namespace ServiceStack.OrmLite.Tests.Support
+{
+    public class Artist
+    {
+        public int Id { get; set; }
+        public string Name { get; set; }
+
+        [Reference]
+        public List<Track> Tracks { get; set; }
+        public override string ToString() => Name;
+    }
+
+    public class Track
+    {
+        [AutoIncrement]
+        public int Id { get; set; }
+        public string Name { get; set; }
+        public int ArtistId { get; set; }
+        public string Album { get; set; }
+        public int Year { get; set; }
+        public override string ToString() => Name;
+    }
+
+    public class ArtistTrackTestBase : OrmLiteTestBase
+    {
+        static readonly Artist[] Artists = {
+            new Artist {
+                Id = 1, Name = "Faith No More",
+                Tracks = new List<Track> {
+                    new Track { Name = "Everythings Ruined", Album = "Angel Dust", Year = 1992 },
+                    new Track { Name = "Ashes to Ashes", Album = "Album of the Year", Year = 1997 },
+                }
+            },
+            new Artist {
+                Id = 2, Name = "Live",
+                Tracks = new List<Track> {
+                    new Track { Name = "Lightning Crashes", Album = "Throwing Copper", Year = 1994 },
+                    new Track { Name = "Lakini's Juice", Album = "Secret Samadhi", Year = 1997 },
+                }
+            },
+            new Artist {
+                Id = 3, Name = "Nirvana",
+                Tracks = new List<Track> {
+                    new Track { Name = "Smells Like Teen Spirit", Album = "Nevermind", Year = 1991  },
+                    new Track { Name = "Heart-Shaped Box", Album = "In Utero", Year = 1993 },
+                }
+            },
+            new Artist {
+                Id = 4, Name = "Pearl Jam",
+                Tracks = new List<Track> {
+                    new Track { Name = "Alive", Album = "Ten", Year = 1991 },
+                    new Track { Name = "Daughter", Album = "Vs", Year = 1993 },
+                }
+            },
+        };
+
+        public IDbConnection CreateArtistAndTrackTablesWithData(IDbConnection db)
+        {
+            db.DropAndCreateTable<Artist>();
+            db.DropAndCreateTable<Track>();
+            Artists.Each(x => db.Save(x, references: true));
+            return db;
+        }
+    }
+}

tests/ServiceStack.OrmLite.Tests/ServiceStack.OrmLite.Tests.csproj

@@ -0,0 +1,29 @@
+using NUnit.Framework;
+using ServiceStack.OrmLite.Tests.Support;
+using ServiceStack.Text;
+
+namespace ServiceStack.OrmLite.Tests.UseCase
+{
+    [TestFixture]
+    public class ArtistTrackSqlExpressions : ArtistTrackTestBase
+    {
+        [Test]
+        public void Can_OrderBy_Column_Index()
+        {
+            using (var db = CreateArtistAndTrackTablesWithData(OpenDbConnection()))
+            {
+                var q = db.From<Track>()
+                    .Where(x => x.Year > 1991)
+                    .And(x => x.Name.Contains("A"))
+                    .GroupBy(x => x.Year)
+                    .OrderByDescending(2)
+                    .ThenBy(x => x.Year)
+                    .Take(1)
+                    .Select(x => new { x.Year, Count = Sql.Count("*") });
+
+                var result = db.Dictionary<int, int>(q);
+                Assert.That(result[1993], Is.EqualTo(2));
+            }
+        }
+    }
+}