common builder interface makes sense probably for future.

PoweredSoft.DynamicLinq/Fluent/Group/GroupBuilder.cs

@@ -6,7 +6,7 @@ using PoweredSoft.DynamicLinq.Helpers;
 
 namespace PoweredSoft.DynamicLinq.Fluent
 {
-    public class GroupBuilder
+    public class GroupBuilder : IQueryBuilder
     {
         public List<(string path, string propertyName)> Parts { get; set; } = new List<(string path, string propertyName)>();
         public Type Type { get; set; }

PoweredSoft.DynamicLinq/Fluent/OrderBy/OrderByBuilder.cs

@@ -6,7 +6,7 @@ using System.Text;
 
 namespace PoweredSoft.DynamicLinq.Fluent
 {
-    public class OrderByBuilder
+    public class OrderByBuilder : IQueryBuilder
     {
         public IQueryable Query { get; }
 

PoweredSoft.DynamicLinq/Fluent/Select/SelectBuilder.cs

@@ -13,7 +13,7 @@ namespace PoweredSoft.DynamicLinq.Fluent
         public SelectTypes SelectType { get; set; }
     }
 
-    public class SelectBuilder
+    public class SelectBuilder : IQueryBuilder
     {
         public List<SelectPart> Parts = new List<SelectPart>();
         public Type DestinationType { get; set; }

PoweredSoft.DynamicLinq/Fluent/WhereBuilder/WhereBuilder.cs

@@ -8,7 +8,7 @@ using System.Threading.Tasks;
 
 namespace PoweredSoft.DynamicLinq.Fluent
 {
-    public partial class WhereBuilder
+    public partial class WhereBuilder : IQueryBuilder
     {
         public IQueryable Query { get; set; }
         public Type QueryableType { get; set; }

PoweredSoft.DynamicLinq/Interfaces/IQueryBuilder.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace PoweredSoft.DynamicLinq
+{
+    public interface IQueryBuilder
+    {
+        IQueryable Query { get; }
+
+        IQueryable Build();
+    }
+}