Support conditional expression in projection

src/EntityFramework.MicrosoftSqlServer/Query/Sql/Internal/SqlServerQuerySqlGenerator.cs

@@ -1,13 +1,15 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
 using JetBrains.Annotations;
 using Microsoft.Data.Entity.Query.Expressions;
 using Microsoft.Data.Entity.Query.Expressions.Internal;
 using Microsoft.Data.Entity.Storage;
 using Microsoft.Data.Entity.Utilities;
+using Remotion.Linq.Parsing;
 
 namespace Microsoft.Data.Entity.Query.Sql.Internal
 {
@@ -20,10 +22,10 @@ public SqlServerQuerySqlGenerator(
             [NotNull] IRelationalTypeMapper relationalTypeMapper,
             [NotNull] SelectExpression selectExpression)
             : base(
-                  relationalCommandBuilderFactory, 
-                  sqlGenerationHelper, 
-                  parameterNameGeneratorFactory, 
-                  relationalTypeMapper, 
+                  relationalCommandBuilderFactory,
+                  sqlGenerationHelper,
+                  parameterNameGeneratorFactory,
+                  relationalTypeMapper,
                   selectExpression)
         {
         }
@@ -69,6 +71,14 @@ protected override void GenerateLimitOffset(SelectExpression selectExpression)
             base.GenerateLimitOffset(selectExpression);
         }
 
+        protected override void VisitProjection(IReadOnlyList<Expression> projections)
+        {
+            var comparisonTransformer = new ProjectionComparisonTransformingVisitor();
+            var transformedProjections = projections.Select(comparisonTransformer.Visit).ToList();
+
+            base.VisitProjection(transformedProjections);
+        }
+
         public virtual Expression VisitRowNumber(RowNumberExpression rowNumberExpression)
         {
             Check.NotNull(rowNumberExpression, nameof(rowNumberExpression));
@@ -89,5 +99,59 @@ public override Expression VisitSqlFunction(SqlFunctionExpression sqlFunctionExp
             }
             return base.VisitSqlFunction(sqlFunctionExpression);
         }
+
+        private class ProjectionComparisonTransformingVisitor : RelinqExpressionVisitor
+        {
+            protected override Expression VisitUnary(UnaryExpression node)
+            {
+                if (node.NodeType == ExpressionType.Not
+                    && node.Operand is AliasExpression)
+                {
+                    return Expression.Condition(
+                        node,
+                        Expression.Constant(true, typeof(bool)),
+                        Expression.Constant(false, typeof(bool)));
+                }
+
+                return base.VisitUnary(node);
+            }
+
+            protected override Expression VisitBinary(BinaryExpression node)
+            {
+                if (node.IsComparisonOperation())
+                {
+                    return Expression.Condition(
+                        node,
+                        Expression.Constant(true, typeof(bool)),
+                        Expression.Constant(false, typeof(bool)));
+                }
+
+                return base.VisitBinary(node);
+            }
+
+
+            protected override Expression VisitConditional(ConditionalExpression node)
+            {
+                var test = Visit(node.Test);
+                if (test is AliasExpression)
+                {
+                    return Expression.Condition(
+                        Expression.Equal(test, Expression.Constant(true, typeof(bool))),
+                        Visit(node.IfTrue),
+                        Visit(node.IfFalse));
+                }
+
+                var condition = test as ConditionalExpression;
+                if (condition != null)
+                {
+                    return Expression.Condition(
+                        condition.Test,
+                        Visit(node.IfTrue),
+                        Visit(node.IfFalse));
+                }
+                return base.VisitConditional(node);
+            }
+        }
+
     }
 }

src/EntityFramework.Relational/Extensions/ExpressionExtensions.cs

@@ -19,6 +19,18 @@ public static bool IsLogicalOperation([NotNull] this Expression expression)
                    || (expression.NodeType == ExpressionType.OrElse);
         }
 
+        public static bool IsComparisonOperation([NotNull] this Expression expression)
+        {
+            Check.NotNull(expression, nameof(expression));
+
+            return expression.NodeType == ExpressionType.Equal
+                || expression.NodeType == ExpressionType.NotEqual
+                || expression.NodeType == ExpressionType.LessThan
+                || expression.NodeType == ExpressionType.LessThanOrEqual
+                || expression.NodeType == ExpressionType.GreaterThan
+                || expression.NodeType == ExpressionType.GreaterThanOrEqual;
+        }
+
         public static ColumnExpression TryGetColumnExpression([NotNull] this Expression expression)
             => (expression as AliasExpression)?.TryGetColumnExpression();
 

src/EntityFramework.Relational/Query/Sql/DefaultQuerySqlGenerator.cs

@@ -143,7 +143,7 @@ public virtual Expression VisitSelect(SelectExpression selectExpression)
                     _relationalCommandBuilder.Append(", ");
                 }
 
-                VisitJoin(selectExpression.Projection);
+                VisitProjection(selectExpression.Projection);
 
                 projectionAdded = true;
             }
@@ -227,6 +227,13 @@ var predicate
             return selectExpression;
         }
 
+        protected virtual void VisitProjection([NotNull] IReadOnlyList<Expression> projections)
+        {
+            var nullComparisonTransformer = new NullComparisonTransformingVisitor(_parametersValues);
+
+            VisitJoin(projections.Select(e => nullComparisonTransformer.Visit(e)).ToList());
+        }
+
         protected virtual void GenerateOrderBy([NotNull] IReadOnlyList<Ordering> orderings)
         {
             _relationalCommandBuilder.Append("ORDER BY ");
@@ -1169,4 +1176,4 @@ var columnExpression
             }
         }
     }
-}
+}

test/EntityFramework.Core.FunctionalTests/AsyncQueryTestBase.cs

@@ -1216,6 +1216,13 @@ await AssertQuery<Customer>(
                 cs => cs.Select(c => new { c.City, c.Phone, c.Country }));
         }
 
+        [ConditionalFact]
+        public virtual async Task Select_anonymous_conditional_expression()
+        {
+            await AssertQuery<Product>(
+                ps => ps.Select(p => new { p.ProductID, IsAvailable = p.UnitsInStock > 0 }));
+        }
+
         [ConditionalFact]
         public virtual async Task Select_customer_table()
         {

test/EntityFramework.Core.FunctionalTests/GearsOfWarQueryTestBase.cs

@@ -502,6 +502,72 @@ public virtual void Where_nullable_enum_with_nullable_parameter()
             }
         }
 
+        [ConditionalFact]
+        public virtual void Select_inverted_boolean()
+        {
+            using (var context = CreateContext())
+            {
+                var automaticWeapons = context.Weapons
+                    .Where(w => w.IsAutomatic)
+                    .Select(w => new { w.Id, Manual = !w.IsAutomatic })
+                    .ToList();
+
+                Assert.True(automaticWeapons.All(t => t.Manual == false));
+            }
+        }
+
+        [ConditionalFact]
+        public virtual void Select_comparison_with_null()
+        {
+            AmmunitionType? ammunitionType = AmmunitionType.Cartridge;
+            using (var context = CreateContext())
+            {
+                var cartidgeWeapons = context.Weapons
+                    .Where(w => w.AmmunitionType == ammunitionType)
+                    .Select(w => new { w.Id, Cartidge = w.AmmunitionType == ammunitionType })
+                    .ToList();
+
+                Assert.True(cartidgeWeapons.All(t => t.Cartidge == true));
+            }
+
+            ammunitionType = null;
+            using (var context = CreateContext())
+            {
+                var cartidgeWeapons = context.Weapons
+                    .Where(w => w.AmmunitionType == ammunitionType)
+                    .Select(w => new { w.Id, Cartidge = w.AmmunitionType == ammunitionType })
+                    .ToList();
+
+                Assert.True(cartidgeWeapons.All(t => t.Cartidge == true));
+            }
+        }
+
+        [ConditionalFact]
+        public virtual void Select_ternary_operation_with_boolean()
+        {
+            using (var context = CreateContext())
+            {
+                var weapons = context.Weapons
+                    .Select(w => new { w.Id, Num = w.IsAutomatic ? 1 : 0})
+                    .ToList();
+
+                Assert.Equal(3, weapons.Count(w => w.Num == 1));
+            }
+        }
+
+        [ConditionalFact]
+        public virtual void Select_ternary_operation_with_inverted_boolean()
+        {
+            using (var context = CreateContext())
+            {
+                var weapons = context.Weapons
+                    .Select(w => new { w.Id, Num = !w.IsAutomatic ? 1 : 0 })
+                    .ToList();
+
+                Assert.Equal(7, weapons.Count(w => w.Num == 1));
+            }
+        }
+
         [ConditionalFact]
         public virtual void Select_Where_Navigation()
         {

test/EntityFramework.Core.FunctionalTests/QueryTestBase.cs

@@ -1230,7 +1230,7 @@ public virtual void Where_select_many_and()
             AssertQuery<Customer, Employee>((cs, es) =>
                 from c in cs
                 from e in es
-                // ReSharper disable ArrangeRedundantParentheses
+                    // ReSharper disable ArrangeRedundantParentheses
                 where (c.City == "London" && c.Country == "UK")
                         && (e.City == "London" && e.Country == "UK")
                 select new { c, e });
@@ -1597,6 +1597,13 @@ public virtual void Select_anonymous_bool_constant_in_expression()
                 cs => cs.Select(c => new { c.CustomerID, Expression = c.CustomerID.Length + 5 }));
         }
 
+        [ConditionalFact]
+        public virtual void Select_anonymous_conditional_expression()
+        {
+            AssertQuery<Product>(
+                ps => ps.Select(p => new { p.ProductID, IsAvailable = p.UnitsInStock > 0 }));
+        }
+
         [ConditionalFact]
         public virtual void Select_customer_table()
         {
@@ -4474,7 +4481,7 @@ public virtual void Select_take_skip_null_coalesce_operator2()
         public virtual void Select_take_skip_null_coalesce_operator3()
         {
             AssertQuery<Customer>(
-                cs => cs.OrderBy(c => c.Region ?? "ZZ").Take(10).Skip(5), 
+                cs => cs.OrderBy(c => c.Region ?? "ZZ").Take(10).Skip(5),
                 entryCount: 5);
         }
 
@@ -4561,9 +4568,9 @@ public virtual void Select_Subquery_Single()
             {
                 var orderDetails
                     = (from od in context.Set<OrderDetail>()
-                        select (from o in context.Set<Order>()
-                            where od.OrderID == o.OrderID
-                            select o).First())
+                       select (from o in context.Set<Order>()
+                               where od.OrderID == o.OrderID
+                               select o).First())
                         .Take(2)
                         .ToList();
 

test/EntityFramework.Core.FunctionalTests/TestModels/GearsOfWarModel/GearsOfWarModelInitializer.cs

@@ -66,61 +66,71 @@ public static void Seed(GearsOfWarContext context)
                 var marcusLancer = new Weapon
                     {
                         Name = "Marcus' Lancer",
-                        AmmunitionType = AmmunitionType.Cartridge
+                        AmmunitionType = AmmunitionType.Cartridge,
+                        IsAutomatic = true
                     };
 
                 var marcusGnasher = new Weapon
                     {
                         Name = "Marcus' Gnasher",
                         AmmunitionType = AmmunitionType.Shell,
+                        IsAutomatic = false,
                         SynergyWith = marcusLancer
                     };
 
                 var domsHammerburst = new Weapon
                     {
                         Name = "Dom's Hammerburst",
-                        AmmunitionType = AmmunitionType.Cartridge
+                        AmmunitionType = AmmunitionType.Cartridge,
+                        IsAutomatic = false
                     };
 
                 var domsGnasher = new Weapon
                     {
                         Name = "Dom's Gnasher",
-                        AmmunitionType = AmmunitionType.Shell
+                        AmmunitionType = AmmunitionType.Shell,
+                        IsAutomatic = false
                     };
 
                 var colesGnasher = new Weapon
                     {
                         Name = "Cole's Gnasher",
-                        AmmunitionType = AmmunitionType.Shell
+                        AmmunitionType = AmmunitionType.Shell,
+                        IsAutomatic = false
                     };
 
                 var colesMulcher = new Weapon
                     {
                         Name = "Cole's Mulcher",
-                        AmmunitionType = AmmunitionType.Cartridge
+                        AmmunitionType = AmmunitionType.Cartridge,
+                        IsAutomatic = true
                     };
 
                 var bairdsLancer = new Weapon
                     {
                         Name = "Baird's Lancer",
-                        AmmunitionType = AmmunitionType.Cartridge
+                        AmmunitionType = AmmunitionType.Cartridge,
+                        IsAutomatic = true
                     };
 
                 var bairdsGnasher = new Weapon
                     {
                         Name = "Baird's Gnasher",
-                        AmmunitionType = AmmunitionType.Shell
+                        AmmunitionType = AmmunitionType.Shell,
+                        IsAutomatic = false
                     };
 
                 var paduksMarkza = new Weapon
                     {
                         Name = "Paduk's Markza",
-                        AmmunitionType = AmmunitionType.Cartridge
+                        AmmunitionType = AmmunitionType.Cartridge,
+                        IsAutomatic = false
                     };
 
                 var maulersFlail = new Weapon
                     {
-                        Name = "Mauler's Flail"
+                        Name = "Mauler's Flail",
+                        IsAutomatic = false
                     };
 
                 context.Weapons.Add(marcusLancer);
@@ -228,7 +238,7 @@ public static void Seed(GearsOfWarContext context)
                     };
 
                 var marcus = new Officer
-                {
+                    {
                         Nickname = "Marcus",
                         FullName = "Marcus Fenix",
                         SquadId = deltaSquad.Id,

test/EntityFramework.Core.FunctionalTests/TestModels/GearsOfWarModel/Weapon.cs

@@ -9,6 +9,7 @@ public class Weapon
         public int Id { get; set; }
         public string Name { get; set; }
         public AmmunitionType? AmmunitionType { get; set; }
+        public bool IsAutomatic { get; set; }
 
         // 1 - 1 self reference
         public int? SynergyWithId { get; set; }

test/EntityFramework.MicrosoftSqlServer.FunctionalTests/GearsOfWarFromSqlQuerySqlServerTest.cs

@@ -14,7 +14,7 @@ public override void From_sql_queryable_simple_columns_out_of_order()
             base.From_sql_queryable_simple_columns_out_of_order();
 
             Assert.Equal(
-                @"SELECT ""Id"", ""Name"", ""AmmunitionType"", ""OwnerFullName"", ""SynergyWithId"" FROM ""Weapon"" ORDER BY ""Name""",
+                @"SELECT ""Id"", ""Name"", ""IsAutomatic"", ""AmmunitionType"", ""OwnerFullName"", ""SynergyWithId"" FROM ""Weapon"" ORDER BY ""Name""",
                 Sql);
         }