--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/UnitTests/Linq/ConvertExpression.cs	Thu Mar 27 21:46:09 2014 +0400
@@ -0,0 +1,515 @@
+using System;
+using System.Linq;
+
+using BLToolkit.Data.DataProvider;
+
+using NUnit.Framework;
+
+namespace Data.Linq
+{
+	[TestFixture]
+	public class ConvertExpression : TestBase
+	{
+		[Test]
+		public void Select1()
+		{
+			ForEachProvider(db => AreEqual(
+				from p in Parent
+				let children = p.Children.Where(c => c.ParentID > 1)
+				select children.Sum(c => c.ChildID),
+				from p in db.Parent
+				let children = p.Children.Where(c => c.ParentID > 1)
+				select children.Sum(c => c.ChildID)));
+		}
+
+		[Test]
+		public void Select2()
+		{
+			ForEachProvider(db => AreEqual(
+				from p in Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				let children2 = children1.Where(c => c.ParentID < 10)
+				select children2.Sum(c => c.ChildID),
+				from p in db.Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				let children2 = children1.Where(c => c.ParentID < 10)
+				select children2.Sum(c => c.ChildID)));
+		}
+
+		[Test]
+		public void Select3()
+		{
+			ForEachProvider(db => AreEqual(
+				Parent
+					.Select(p => new { children1 = p.Children. Where(c => c.ParentID > 1)  })
+					.Select(t => new { children2 = t.children1.Where(c => c.ParentID < 10) })
+					.Select(t => t.children2.Sum(c => c.ChildID)),
+				db.Parent
+					.Select(p => new { children1 = p.Children. Where(c => c.ParentID > 1)  })
+					.Select(t => new { children2 = t.children1.Where(c => c.ParentID < 10) })
+					.Select(t => t.children2.Sum(c => c.ChildID))));
+		}
+
+		[Test]
+		public void Select4()
+		{
+			ForEachProvider(db => AreEqual(
+				Parent
+					.Select(p => p.Children. Where(c => c.ParentID > 1))
+					.Select(t => t.Where(c => c.ParentID < 10))
+					.Select(t => t.Sum(c => c.ChildID)),
+				db.Parent
+					.Select(p => p.Children. Where(c => c.ParentID > 1))
+					.Select(t => t.Where(c => c.ParentID < 10))
+					.Select(t => t.Sum(c => c.ChildID))));
+		}
+
+		[Test]
+		public void Where1()
+		{
+			ForEachProvider(db => AreEqual(
+				from p in Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				let children2 = children1.Where(c => c.ParentID < 10)
+				where children1.Any()
+				select children2.Sum(c => c.ChildID),
+				from p in db.Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				let children2 = children1.Where(c => c.ParentID < 10)
+				where children1.Any()
+				select children2.Sum(c => c.ChildID)));
+		}
+
+		[Test]
+		public void Where2()
+		{
+			ForEachProvider(db => AreEqual(
+				from p in Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				where children1.Any()
+				let children2 = children1.Where(c => c.ParentID < 10)
+				select children2.Sum(c => c.ChildID),
+				from p in db.Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				where children1.Any()
+				let children2 = children1.Where(c => c.ParentID < 10)
+				select children2.Sum(c => c.ChildID)));
+		}
+
+		[Test]
+		public void Where3()
+		{
+			ForEachProvider(db => AreEqual(
+				from p in Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				let children2 = children1.Where(c => c.ParentID < 10)
+				where children2.Any()
+				select children2.Sum(c => c.ChildID),
+				from p in db.Parent
+				let children1 = p.Children.Where(c => c.ParentID > 1)
+				let children2 = children1.Where(c => c.ParentID < 10)
+				where children2.Any()
+				select children2.Sum(c => c.ChildID)));
+		}
+
+		//[Test]
+		public void Where4()
+		{
+			ForEachProvider(db => AreEqual(
+				   Parent
+					.Select(p => new { p, children1 = p.Children. Where(c => c.ParentID > 1)  })
+					.Where (t => t.children1.Any()),
+				db.Parent
+					.Select(p => new { p, children1 = p.Children. Where(c => c.ParentID > 1)  })
+					.Where (t => t.children1.Any())));
+		}
+
+		//[Test]
+		public void Where5()
+		{
+			ForEachProvider(db => AreEqual(
+				   Parent
+					.Select(p => new { children1 = p.Children. Where(c => c.ParentID > 1)  })
+					.Where (t => t.children1.Any()),
+				db.Parent
+					.Select(p => new { children1 = p.Children. Where(c => c.ParentID > 1)  })
+					.Where (t => t.children1.Any())));
+		}
+
+		//[Test]
+		public void Where6()
+		{
+			ForEachProvider(db => AreEqual(
+				   Parent
+					.Select(p => p.Children. Where(c => c.ParentID > 1))
+					.Where (t => t.Any()),
+				db.Parent
+					.Select(p => p.Children. Where(c => c.ParentID > 1))
+					.Where (t => t.Any())));
+		}
+
+		[Test]
+		public void Any1()
+		{
+			ForEachProvider(db => Assert.AreEqual(
+				   Parent
+					.Select(p => new { p, children1 = p.Children.Where(c => c.ParentID > 1) })
+					.Any(p => p.children1.Any()),
+				db.Parent
+					.Select(p => new { p, children1 = p.Children.Where(c => c.ParentID > 1) })
+					.Any(p => p.children1.Any())));
+		}
+
+		[Test]
+		public void Any2()
+		{
+			ForEachProvider(db => Assert.AreEqual(
+				   Parent
+					.Select(p => p.Children.Where(c => c.ParentID > 1))
+					.Any(p => p.Any()),
+				db.Parent
+					.Select(p => p.Children.Where(c => c.ParentID > 1))
+					.Any(p => p.Any())));
+		}
+
+		[Test]
+		public void Any3()
+		{
+			ForEachProvider(db => Assert.AreEqual(
+				   Parent
+					.Select(p => new { p, children1 = p.Children.Where(c => c.ParentID > 1) })
+					.Where(p => p.children1.Any())
+					.Any(),
+				db.Parent
+					.Select(p => new { p, children1 = p.Children.Where(c => c.ParentID > 1) })
+					.Where(p => p.children1.Any())
+					.Any()));
+		}
+
+		//[Test]
+		public void Any4()
+		{
+			ForEachProvider(db => Assert.AreEqual(
+				   Parent
+					.Select(p => new { children1 = p.Children.Where(c => c.ParentID > 1) })
+					.Where(p => p.children1.Any())
+					.Any(),
+				db.Parent
+					.Select(p => new { children1 = p.Children.Where(c => c.ParentID > 1) })
+					.Where(p => p.children1.Any())
+					.Any()));
+		}
+
+
+		[Test]
+		public void LetTest1([DataContexts(ProviderName.SqlCe, ProviderName.Informix, ProviderName.Sybase)] string context)
+		{
+			using (var db = GetDataContext(context))
+				AreEqual(
+					from p in Parent
+					let ch = p.Children
+					where ch.FirstOrDefault() != null
+					select ch.FirstOrDefault().ParentID
+					,
+					from p in db.Parent
+					let ch = p.Children
+					where ch.FirstOrDefault() != null
+					select ch.FirstOrDefault().ParentID);
+		}
+
+		[Test]
+		public void LetTest2()
+		{
+			ForEachProvider(
+				new[] { ProviderName.SqlCe, ProviderName.Informix, ProviderName.Sybase },
+				db => AreEqual(
+					from p in Parent
+					let ch = p.Children
+					where ch.FirstOrDefault() != null
+					select p
+					,
+					from p in db.Parent
+					let ch = p.Children
+					where ch.FirstOrDefault() != null
+					select p));
+		}
+
+		[Test]
+		public void LetTest3()
+		{
+			ForEachProvider(
+				new[] { ProviderName.Informix, ProviderName.Sybase },
+				db => AreEqual(
+					from p in Parent
+					let ch = Child
+					select ch.FirstOrDefault().ParentID
+					,
+					from p in db.Parent
+					let ch = db.Child
+					select ch.FirstOrDefault().ParentID));
+		}
+
+		[Test]
+		public void LetTest4()
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = true;
+
+			ForEachProvider(
+				new[] { ProviderName.Informix, ProviderName.Sybase },
+				db => AreEqual(
+					from p in Parent
+					let ch1 = Child.Where(c => c.ParentID == p.ParentID)
+					let ch2 = ch1.Where(c => c.ChildID > -100)
+					select new
+					{
+						Any    = ch2.Any(),
+						Count  = ch2.Count(),
+						First1 = ch2.FirstOrDefault(c => c.ParentID > 0),
+						First2 = ch2.FirstOrDefault()
+					}
+					,
+					from p in db.Parent
+					let ch1 = db.Child.Where(c => c.ParentID == p.ParentID)
+					let ch2 = ch1.Where(c => c.ChildID > -100)
+					select new
+					{
+						Any    = ch2.Any(),
+						Count  = ch2.Count(),
+						First1 = ch2.FirstOrDefault(c => c.ParentID > 0),
+						First2 = ch2.FirstOrDefault()
+					}));
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+
+		[Test]
+		public void LetTest5()
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = true;
+
+			ForEachProvider(
+				new[] { ProviderName.Informix, ProviderName.Sybase },
+				db => AreEqual(
+					from p in Parent
+					let ch1 = Child.Where(c => c.ParentID == p.ParentID)
+					let ch2 = ch1.Where(c => c.ChildID > -100)
+					select new
+					{
+						Any    = ch2.Any(),
+						Count  = ch2.Count(),
+						First1 = ch2.FirstOrDefault(c => c.ParentID > 0) == null ? 0 : ch2.FirstOrDefault(c => c.ParentID > 0).ParentID,
+						First2 = ch2.FirstOrDefault()
+					}
+					,
+					from p in db.Parent
+					let ch1 = db.Child.Where(c => c.ParentID == p.ParentID)
+					let ch2 = ch1.Where(c => c.ChildID > -100)
+					select new
+					{
+						Any    = ch2.Any(),
+						Count  = ch2.Count(),
+						First1 = ch2.FirstOrDefault(c => c.ParentID > 0).ParentID,
+						First2 = ch2.FirstOrDefault()
+					}));
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+
+		[Test]
+		public void LetTest6()
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery     = true;
+			//BLToolkit.Common.Configuration.Linq.GenerateExpressionTest = true;
+
+			ForEachProvider(
+				new[] { ProviderName.Informix, ProviderName.Sybase },
+				db => AreEqual(
+					(
+						from p in Parent
+						let ch1 = Child.Where(c => c.ParentID == p.ParentID)
+						let ch2 = ch1.Where(c => c.ChildID > -100)
+						select new
+						{
+							p.ParentID,
+							Any    = ch2.Any(),
+							Count  = ch2.Count(),
+							First1 = ch2.FirstOrDefault(c => c.ParentID > 0) == null ? 0 : ch2.FirstOrDefault(c => c.ParentID > 0).ParentID,
+							First2 = ch2.FirstOrDefault()
+						}
+					).Where(t => t.ParentID > 0)
+					,
+					(
+						from p in db.Parent
+						let ch1 = db.Child.Where(c => c.ParentID == p.ParentID)
+						let ch2 = ch1.Where(c => c.ChildID > -100)
+						select new
+						{
+							p.ParentID,
+							Any    = ch2.Any(),
+							Count  = ch2.Count(),
+							First1 = ch2.FirstOrDefault(c => c.ParentID > 0).ParentID,
+							First2 = ch2.FirstOrDefault()
+						}
+					).Where(t => t.ParentID > 0)));
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+
+		[Test]
+		public void LetTest7()
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = true;
+
+			ForEachProvider(
+				new[] { ProviderName.Informix, ProviderName.Sybase },
+				db => AreEqual(
+					(
+						from p in Parent
+						let ch1 = Child.Where(c => c.ParentID == p.ParentID)
+						let ch2 = ch1.Where(c => c.ChildID > -100)
+						select new
+						{
+							p.ParentID,
+							Any    = ch2.Any(),
+							Count  = ch2.Count(),
+							First1 = ch2.FirstOrDefault(c => c.ParentID > 0) == null ? 0 : ch2.FirstOrDefault(c => c.ParentID > 0).ParentID,
+							First2 = ch2.FirstOrDefault()
+						}
+					).Where(t => t.ParentID > 0).Take(5000)
+					,
+					(
+						from p in db.Parent
+						let ch1 = db.Child.Where(c => c.ParentID == p.ParentID)
+						let ch2 = ch1.Where(c => c.ChildID > -100)
+						select new
+						{
+							p.ParentID,
+							Any    = ch2.Any(),
+							Count  = ch2.Count(),
+							First1 = ch2.FirstOrDefault(c => c.ParentID > 0).ParentID,
+							First2 = ch2.FirstOrDefault()
+						}
+					).Where(t => t.ParentID > 0).Take(5000)));
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+
+		[Test]
+		public void LetTest8()
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = true;
+
+			ForEachProvider(
+				db => AreEqual(
+					from p in Parent
+					let ch1 = Child.Where(c => c.ParentID == p.ParentID)
+					let ch2 = ch1.Where(c => c.ChildID > -100)
+					let ch3	= ch2.FirstOrDefault(c => c.ParentID > 0)
+					select new
+					{
+						First1 = ch3 == null ? 0 : ch3.ParentID,
+						Any    = ch2.Any(),
+						Count  = ch2.Count(),
+						First2 = ch2.FirstOrDefault()
+					}
+					,
+					from p in db.Parent
+					let ch1 = db.Child.Where(c => c.ParentID == p.ParentID)
+					let ch2 = ch1.Where(c => c.ChildID > -100)
+					let ch3	= ch2.FirstOrDefault(c => c.ParentID > 0)
+					select new
+					{
+						First1 = ch3 == null ? 0 : ch3.ParentID,
+						Any    = ch2.Any(),
+						Count  = ch2.Count(),
+						First2 = ch2.FirstOrDefault()
+					}));
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+
+		[Test]
+		public void LetTest9()
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = true;
+
+			ForEachProvider(
+				db => AreEqual(
+					(
+						from p in Parent
+						let ch1 = Child.Where(c => c.ParentID == p.ParentID)
+						select new
+						{
+							First = ch1.FirstOrDefault()
+						}
+					).Take(10)
+					,
+					(
+						from p in db.Parent
+						let ch1 = db.Child.Where(c => c.ParentID == p.ParentID)
+						select new
+						{
+							First = ch1.FirstOrDefault()
+						}
+					).Take(10)));
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+
+		[Test]
+		public void LetTest10()
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = true;
+
+			ForEachProvider(
+				db => Assert.AreEqual(
+					(
+						from p in Parent
+						let ch1 = Child.Where(c => c.ParentID == p.ParentID)
+						select new
+						{
+							First = ch1.FirstOrDefault()
+						}
+					).Any()
+					,
+					(
+						from p in db.Parent
+						let ch1 = db.Child.Where(c => c.ParentID == p.ParentID)
+						select new
+						{
+							First = ch1.FirstOrDefault()
+						}
+					).Any()));
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+
+		[Test]
+		public void LetTest11([DataContexts] string context)
+		{
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = true;
+
+			using (var db = GetDataContext(context))
+				AreEqual(
+					from p in Parent
+					let ch1 = Child.FirstOrDefault(c => c.ParentID > 0)
+					let ch2 = Child.Where(c => c.ChildID > -100)
+					select new
+					{
+						First1 = ch1 == null ? 0 : ch1.ParentID,
+						First2 = ch2.FirstOrDefault()
+					}
+					,
+					from p in db.Parent
+					let ch1 = db.Child.FirstOrDefault(c => c.ParentID > 0)
+					let ch2 = Child.Where(c => c.ChildID > -100)
+					select new
+					{
+						First1 = ch1 == null ? 0 : ch1.ParentID,
+						First2 = ch2.FirstOrDefault()
+					});
+
+			BLToolkit.Common.Configuration.Linq.AllowMultipleQuery = false;
+		}
+	}
+}