Implement right join support

Closes #35367

Author: roji

src/EFCore.Cosmos/Query/Internal/CosmosQueryableMethodTranslatingExpressionVisitor.cs

@@ -807,6 +807,23 @@ protected override ShapedQueryExpression TranslateCast(ShapedQueryExpression sou
         return null;
     }
 
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    protected override ShapedQueryExpression? TranslateRightJoin(
+        ShapedQueryExpression outer,
+        ShapedQueryExpression inner,
+        LambdaExpression outerKeySelector,
+        LambdaExpression innerKeySelector,
+        LambdaExpression resultSelector)
+    {
+        AddTranslationErrorDetails(CosmosStrings.CrossDocumentJoinNotSupported);
+        return null;
+    }
+
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in

src/EFCore.InMemory/Query/Internal/InMemoryQueryableMethodTranslatingExpressionVisitor.cs

@@ -833,6 +833,20 @@ static bool IsConvertedToNullable(Expression outer, Expression inner)
         return source;
     }
 
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    protected override ShapedQueryExpression? TranslateRightJoin(
+        ShapedQueryExpression outer,
+        ShapedQueryExpression inner,
+        LambdaExpression outerKeySelector,
+        LambdaExpression innerKeySelector,
+        LambdaExpression resultSelector)
+        => null;
+
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in

src/EFCore.Relational/Query/Internal/RelationalValueConverterCompensatingExpressionVisitor.cs

@@ -35,11 +35,11 @@ public RelationalValueConverterCompensatingExpressionVisitor(
     protected override Expression VisitExtension(Expression extensionExpression)
         => extensionExpression switch
         {
-            ShapedQueryExpression shapedQueryExpression => VisitShapedQueryExpression(shapedQueryExpression),
-            CaseExpression caseExpression => VisitCase(caseExpression),
-            SelectExpression selectExpression => VisitSelect(selectExpression),
-            InnerJoinExpression innerJoinExpression => VisitInnerJoin(innerJoinExpression),
-            LeftJoinExpression leftJoinExpression => VisitLeftJoin(leftJoinExpression),
+            ShapedQueryExpression shapedQuery => VisitShapedQueryExpression(shapedQuery),
+            CaseExpression @case => VisitCase(@case),
+            SelectExpression select => VisitSelect(select),
+            PredicateJoinExpressionBase join => VisitJoin(join),
+
             _ => base.VisitExtension(extensionExpression)
         };
 
@@ -86,20 +86,12 @@ private Expression VisitSelect(SelectExpression selectExpression)
         return selectExpression.Update(tables, predicate, groupBy, having, projections, orderings, offset, limit);
     }
 
-    private Expression VisitInnerJoin(InnerJoinExpression innerJoinExpression)
-    {
-        var table = (TableExpressionBase)Visit(innerJoinExpression.Table);
-        var joinPredicate = TryCompensateForBoolWithValueConverter((SqlExpression)Visit(innerJoinExpression.JoinPredicate));
-
-        return innerJoinExpression.Update(table, joinPredicate);
-    }
-
-    private Expression VisitLeftJoin(LeftJoinExpression leftJoinExpression)
+    private Expression VisitJoin(PredicateJoinExpressionBase joinExpression)
     {
-        var table = (TableExpressionBase)Visit(leftJoinExpression.Table);
-        var joinPredicate = TryCompensateForBoolWithValueConverter((SqlExpression)Visit(leftJoinExpression.JoinPredicate));
+        var table = (TableExpressionBase)Visit(joinExpression.Table);
+        var joinPredicate = TryCompensateForBoolWithValueConverter((SqlExpression)Visit(joinExpression.JoinPredicate));
 
-        return leftJoinExpression.Update(table, joinPredicate);
+        return joinExpression.Update(table, joinPredicate);
     }
 
     [return: NotNullIfNotNull(nameof(sqlExpression))]

src/EFCore.Relational/Query/QuerySqlGenerator.cs

@@ -1250,6 +1250,20 @@ protected override Expression VisitLeftJoin(LeftJoinExpression leftJoinExpressio
         return leftJoinExpression;
     }
 
+    /// <summary>
+    ///     Generates SQL for a right join.
+    /// </summary>
+    /// <param name="rightJoinExpression">The <see cref="RightJoinExpression" /> for which to generate SQL.</param>
+    protected override Expression VisitRightJoin(RightJoinExpression rightJoinExpression)
+    {
+        _relationalCommandBuilder.Append("RIGHT JOIN ");
+        Visit(rightJoinExpression.Table);
+        _relationalCommandBuilder.Append(" ON ");
+        Visit(rightJoinExpression.JoinPredicate);
+
+        return rightJoinExpression;
+    }
+
     /// <summary>
     ///     Generates SQL for a scalar subquery.
     /// </summary>

src/EFCore.Relational/Query/RelationalQueryableMethodTranslatingExpressionVisitor.cs

@@ -876,6 +876,27 @@ protected override ShapedQueryExpression TranslateIntersect(ShapedQueryExpressio
         return null;
     }
 
+    /// <inheritdoc />
+    protected override ShapedQueryExpression? TranslateRightJoin(
+        ShapedQueryExpression outer,
+        ShapedQueryExpression inner,
+        LambdaExpression outerKeySelector,
+        LambdaExpression innerKeySelector,
+        LambdaExpression resultSelector)
+    {
+        var joinPredicate = CreateJoinPredicate(outer, outerKeySelector, inner, innerKeySelector);
+        if (joinPredicate != null)
+        {
+            var outerSelectExpression = (SelectExpression)outer.QueryExpression;
+            var outerShaperExpression = outerSelectExpression.AddRightJoin(inner, joinPredicate, outer.ShaperExpression);
+            outer = outer.UpdateShaperExpression(outerShaperExpression);
+
+            return TranslateTwoParameterSelector(outer, resultSelector);
+        }
+
+        return null;
+    }
+
     private SqlExpression CreateJoinPredicate(
         ShapedQueryExpression outer,
         LambdaExpression outerKeySelector,

src/EFCore.Relational/Query/SqlExpressionVisitor.cs

@@ -42,6 +42,7 @@ ShapedQueryExpression shapedQueryExpression
             OuterApplyExpression outerApplyExpression => VisitOuterApply(outerApplyExpression),
             ProjectionExpression projectionExpression => VisitProjection(projectionExpression),
             TableValuedFunctionExpression tableValuedFunctionExpression => VisitTableValuedFunction(tableValuedFunctionExpression),
+            RightJoinExpression rightJoinExpression => VisitRightJoin(rightJoinExpression),
             RowNumberExpression rowNumberExpression => VisitRowNumber(rowNumberExpression),
             RowValueExpression rowValueExpression => VisitRowValue(rowValueExpression),
             ScalarSubqueryExpression scalarSubqueryExpression => VisitScalarSubquery(scalarSubqueryExpression),
@@ -193,6 +194,13 @@ ShapedQueryExpression shapedQueryExpression
     /// <returns>The modified expression, if it or any subexpression was modified; otherwise, returns the original expression.</returns>
     protected abstract Expression VisitProjection(ProjectionExpression projectionExpression);
 
+    /// <summary>
+    ///     Visits the children of the right join expression.
+    /// </summary>
+    /// <param name="rightJoinExpression">The expression to visit.</param>
+    /// <returns>The modified expression, if it or any subexpression was modified; otherwise, returns the original expression.</returns>
+    protected abstract Expression VisitRightJoin(RightJoinExpression rightJoinExpression);
+
     /// <summary>
     ///     Visits the children of the table valued function expression.
     /// </summary>

src/EFCore.Relational/Query/SqlExpressions/InnerJoinExpression.cs

@@ -50,10 +50,12 @@ public InnerJoinExpression(
     /// <param name="table">The <see cref="JoinExpressionBase.Table" /> property of the result.</param>
     /// <param name="joinPredicate">The <see cref="PredicateJoinExpressionBase.JoinPredicate" /> property of the result.</param>
     /// <returns>This expression if no children changed, or an expression with the updated children.</returns>
-    public override InnerJoinExpression Update(TableExpressionBase table, SqlExpression joinPredicate)
-        => table != Table || joinPredicate != JoinPredicate
-            ? new InnerJoinExpression(table, joinPredicate, IsPrunable, Annotations)
-            : this;
+    public override JoinExpressionBase Update(TableExpressionBase table, SqlExpression joinPredicate)
+        => table == Table && joinPredicate == JoinPredicate
+            ? this
+            : joinPredicate is SqlConstantExpression { Value: true }
+                ? new CrossJoinExpression(table)
+                : new InnerJoinExpression(table, joinPredicate, IsPrunable, Annotations);
 
     /// <summary>
     ///     Creates a new expression that is like this one, but using the supplied children. If all of the children are the same, it will

src/EFCore.Relational/Query/SqlExpressions/PredicateJoinExpressionBase.cs

@@ -50,7 +50,7 @@ protected override Expression VisitChildren(ExpressionVisitor visitor)
     /// <param name="table">The <see cref="JoinExpressionBase.Table" /> property of the result.</param>
     /// <param name="joinPredicate">The <see cref="PredicateJoinExpressionBase.JoinPredicate" /> property of the result.</param>
     /// <returns>This expression if no children changed, or an expression with the updated children.</returns>
-    public abstract PredicateJoinExpressionBase Update(TableExpressionBase table, SqlExpression joinPredicate);
+    public abstract JoinExpressionBase Update(TableExpressionBase table, SqlExpression joinPredicate);
 
     /// <inheritdoc />
     public override bool Equals(object? obj)

src/EFCore.Relational/Query/SqlExpressions/RightJoinExpression.cs

@@ -0,0 +1,106 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+
+/// <summary>
+///     <para>
+///         An expression that represents a RIGHT JOIN in a SQL tree.
+///     </para>
+///     <para>
+///         This type is typically used by database providers (and other extensions). It is generally
+///         not used in application code.
+///     </para>
+/// </summary>
+public class RightJoinExpression : PredicateJoinExpressionBase
+{
+    private static ConstructorInfo? _quotingConstructor;
+
+    /// <summary>
+    ///     Creates a new instance of the <see cref="LeftJoinExpression" /> class.
+    /// </summary>
+    /// <param name="table">A table source to LEFT JOIN with.</param>
+    /// <param name="joinPredicate">A predicate to use for the join.</param>
+    /// <param name="prunable">Whether this join expression may be pruned if nothing references a column on it.</param>
+    public RightJoinExpression(TableExpressionBase table, SqlExpression joinPredicate, bool prunable = false)
+        : this(table, joinPredicate, prunable, annotations: null)
+    {
+    }
+
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    [EntityFrameworkInternal] // For precompiled queries
+    public RightJoinExpression(
+        TableExpressionBase table,
+        SqlExpression joinPredicate,
+        bool prunable,
+        IReadOnlyDictionary<string, IAnnotation>? annotations = null)
+        : base(table, joinPredicate, prunable, annotations)
+    {
+    }
+
+    /// <summary>
+    ///     Creates a new expression that is like this one, but using the supplied children. If all of the children are the same, it will
+    ///     return this expression.
+    /// </summary>
+    /// <param name="table">The <see cref="JoinExpressionBase.Table" /> property of the result.</param>
+    /// <param name="joinPredicate">The <see cref="PredicateJoinExpressionBase.JoinPredicate" /> property of the result.</param>
+    /// <returns>This expression if no children changed, or an expression with the updated children.</returns>
+    public override RightJoinExpression Update(TableExpressionBase table, SqlExpression joinPredicate)
+        => table != Table || joinPredicate != JoinPredicate
+            ? new RightJoinExpression(table, joinPredicate, IsPrunable, Annotations)
+            : this;
+
+    /// <summary>
+    ///     Creates a new expression that is like this one, but using the supplied children. If all of the children are the same, it will
+    ///     return this expression.
+    /// </summary>
+    /// <param name="table">The <see cref="JoinExpressionBase.Table" /> property of the result.</param>
+    /// <returns>This expression if no children changed, or an expression with the updated children.</returns>
+    public override RightJoinExpression Update(TableExpressionBase table)
+        => table != Table
+            ? new RightJoinExpression(table, JoinPredicate, IsPrunable, Annotations)
+            : this;
+
+    /// <inheritdoc />
+    protected override RightJoinExpression WithAnnotations(IReadOnlyDictionary<string, IAnnotation> annotations)
+        => new(Table, JoinPredicate, IsPrunable, annotations);
+
+    /// <inheritdoc />
+    public override Expression Quote()
+        => New(
+            _quotingConstructor ??= typeof(RightJoinExpression).GetConstructor(
+                [typeof(TableExpressionBase), typeof(SqlExpression), typeof(bool), typeof(IReadOnlyDictionary<string, IAnnotation>)])!,
+            Table.Quote(),
+            JoinPredicate.Quote(),
+            Constant(IsPrunable),
+            RelationalExpressionQuotingUtilities.QuoteAnnotations(Annotations));
+
+    /// <inheritdoc />
+    protected override void Print(ExpressionPrinter expressionPrinter)
+    {
+        expressionPrinter.Append("RIGHT JOIN ");
+        expressionPrinter.Visit(Table);
+        expressionPrinter.Append(" ON ");
+        expressionPrinter.Visit(JoinPredicate);
+        PrintAnnotations(expressionPrinter);
+    }
+
+    /// <inheritdoc />
+    public override bool Equals(object? obj)
+        => obj != null
+            && (ReferenceEquals(this, obj)
+                || obj is RightJoinExpression rightJoinExpression
+                && Equals(rightJoinExpression));
+
+    private bool Equals(RightJoinExpression rightJoinExpression)
+        => base.Equals(rightJoinExpression);
+
+    /// <inheritdoc />
+    public override int GetHashCode()
+        => base.GetHashCode();
+}