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Query: Provide a way to translate aggregate methods on top level #28102

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Jun 14, 2022
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Query: Provide a way to translate aggregate methods on top level #28102

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51 changes: 24 additions & 27 deletions src/EFCore.Relational/Query/Internal/QueryableAggregateMethodTranslator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -79,53 +79,50 @@ public QueryableAggregateMethodTranslator(ISqlExpressionFactory sqlExpressionFac
|| methodInfo == QueryableMethods.CountWithPredicate:
var countSqlExpression = (source.Selector as SqlExpression) ?? _sqlExpressionFactory.Fragment("*");
countSqlExpression = CombineTerms(source, countSqlExpression);
return _sqlExpressionFactory.ApplyDefaultTypeMapping(
_sqlExpressionFactory.Function(
"COUNT",
new[] { countSqlExpression },
nullable: false,
argumentsPropagateNullability: new[] { false },
typeof(int)));
return _sqlExpressionFactory.Function(
"COUNT",
new[] { countSqlExpression },
nullable: false,
argumentsPropagateNullability: new[] { false },
typeof(int));

case nameof(Queryable.LongCount)
when methodInfo == QueryableMethods.LongCountWithoutPredicate
|| methodInfo == QueryableMethods.LongCountWithPredicate:
var longCountSqlExpression = (source.Selector as SqlExpression) ?? _sqlExpressionFactory.Fragment("*");
longCountSqlExpression = CombineTerms(source, longCountSqlExpression);

return _sqlExpressionFactory.ApplyDefaultTypeMapping(
_sqlExpressionFactory.Function(
"COUNT",
new[] { longCountSqlExpression },
nullable: false,
argumentsPropagateNullability: new[] { false },
typeof(long)));
return _sqlExpressionFactory.Function(
"COUNT",
new[] { longCountSqlExpression },
nullable: false,
argumentsPropagateNullability: new[] { false },
typeof(long));

case nameof(Queryable.Max)
when (methodInfo == QueryableMethods.MaxWithoutSelector
|| methodInfo == QueryableMethods.MaxWithSelector)
&& source.Selector is SqlExpression maxSqlExpression:
maxSqlExpression = CombineTerms(source, maxSqlExpression);
return _sqlExpressionFactory.Function(
"MAX",
new[] { maxSqlExpression },
nullable: true,
argumentsPropagateNullability: new[] { false },
maxSqlExpression.Type,
maxSqlExpression.TypeMapping);
"MAX",
new[] { maxSqlExpression },
nullable: true,
argumentsPropagateNullability: new[] { false },
maxSqlExpression.Type,
maxSqlExpression.TypeMapping);

case nameof(Queryable.Min)
when (methodInfo == QueryableMethods.MinWithoutSelector
|| methodInfo == QueryableMethods.MinWithSelector)
&& source.Selector is SqlExpression minSqlExpression:
minSqlExpression = CombineTerms(source, minSqlExpression);
return _sqlExpressionFactory.Function(
"MIN",
new[] { minSqlExpression },
nullable: true,
argumentsPropagateNullability: new[] { false },
minSqlExpression.Type,
minSqlExpression.TypeMapping);
"MIN",
new[] { minSqlExpression },
nullable: true,
argumentsPropagateNullability: new[] { false },
minSqlExpression.Type,
minSqlExpression.TypeMapping);

case nameof(Queryable.Sum)
when (QueryableMethods.IsSumWithoutSelector(methodInfo)
Expand Down
139 changes: 58 additions & 81 deletions src/EFCore.Relational/Query/RelationalQueryableMethodTranslatingExpressionVisitor.cs
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Expand Up @@ -236,8 +236,7 @@ private static ShapedQueryExpression CreateShapedQueryExpression(IEntityType ent
ShapedQueryExpression source,
LambdaExpression? selector,
Type resultType)
=> TranslateAggregateWithSelector(
source, selector, e => TranslateAverage(e), throwWhenEmpty: true, resultType);
=> TranslateAggregateWithSelector(source, selector, QueryableMethods.GetAverageWithoutSelector, throwWhenEmpty: true, resultType);

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateCast(ShapedQueryExpression source, Type resultType)
Expand Down Expand Up @@ -301,7 +300,7 @@ private static ShapedQueryExpression CreateShapedQueryExpression(IEntityType ent

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateCount(ShapedQueryExpression source, LambdaExpression? predicate)
=> TranslateAggregateWithPredicate(source, predicate, e => TranslateCount(e), typeof(int));
=> TranslateAggregateWithPredicate(source, predicate, QueryableMethods.CountWithoutPredicate);

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateDefaultIfEmpty(ShapedQueryExpression source, Expression? defaultValue)
Expand Down Expand Up @@ -386,16 +385,7 @@ private static ShapedQueryExpression CreateShapedQueryExpression(IEntityType ent
LambdaExpression? resultSelector)
{
var selectExpression = (SelectExpression)source.QueryExpression;
// This has it's own set of condition since it is different scenario from below.
// Aggregate operators need pushdown for skip/limit/offset covered by selectExpression.PrepareForAggregate.
// Aggregate operators need special processing beyond pushdown when applying over group by for client eval.
if (selectExpression.Limit != null
|| selectExpression.Offset != null
|| selectExpression.IsDistinct
|| selectExpression.GroupBy.Count > 0)
{
selectExpression.PushdownIntoSubquery();
}
selectExpression.PrepareForAggregate();

var remappedKeySelector = RemapLambdaBody(source, keySelector);
var translatedKey = TranslateGroupingKey(remappedKeySelector);
Expand Down Expand Up @@ -623,15 +613,17 @@ private SqlExpression CreateJoinPredicate(Expression outerKey, Expression innerK

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateLongCount(ShapedQueryExpression source, LambdaExpression? predicate)
=> TranslateAggregateWithPredicate(source, predicate, e => TranslateLongCount(e), typeof(long));
=> TranslateAggregateWithPredicate(source, predicate, QueryableMethods.LongCountWithoutPredicate);

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateMax(ShapedQueryExpression source, LambdaExpression? selector, Type resultType)
=> TranslateAggregateWithSelector(source, selector, e => TranslateMax(e), throwWhenEmpty: true, resultType);
=> TranslateAggregateWithSelector(
source, selector, t => QueryableMethods.MaxWithoutSelector.MakeGenericMethod(t), throwWhenEmpty: true, resultType);

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateMin(ShapedQueryExpression source, LambdaExpression? selector, Type resultType)
=> TranslateAggregateWithSelector(source, selector, e => TranslateMin(e), throwWhenEmpty: true, resultType);
=> TranslateAggregateWithSelector(
source, selector, t => QueryableMethods.MinWithoutSelector.MakeGenericMethod(t), throwWhenEmpty: true, resultType);

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateOfType(ShapedQueryExpression source, Type resultType)
Expand Down Expand Up @@ -888,7 +880,7 @@ protected override Expression VisitMethodCall(MethodCallExpression methodCallExp

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateSum(ShapedQueryExpression source, LambdaExpression? selector, Type resultType)
=> TranslateAggregateWithSelector(source, selector, e => TranslateSum(e), throwWhenEmpty: false, resultType);
=> TranslateAggregateWithSelector(source, selector, QueryableMethods.GetSumWithoutSelector, throwWhenEmpty: false, resultType);

/// <inheritdoc />
protected override ShapedQueryExpression? TranslateTake(ShapedQueryExpression source, Expression count)
Expand Down Expand Up @@ -954,7 +946,12 @@ protected override Expression VisitMethodCall(MethodCallExpression methodCallExp
return source;
}

private SqlExpression? TranslateExpression(Expression expression)
/// <summary>
/// Translates the given expression into equivalent SQL representation.
/// </summary>
/// <param name="expression">An expression to translate.</param>
/// <returns>A <see cref="SqlExpression"/> which is translation of given expression or <see langword="null"/>.</returns>
protected virtual SqlExpression? TranslateExpression(Expression expression)
{
var translation = _sqlTranslator.Translate(expression);
if (translation == null && _sqlTranslator.TranslationErrorDetails != null)
Expand All @@ -965,7 +962,13 @@ protected override Expression VisitMethodCall(MethodCallExpression methodCallExp
return translation;
}

private SqlExpression? TranslateLambdaExpression(
/// <summary>
/// Translates the given lambda expression for the <see cref="ShapedQueryExpression"/> source into equivalent SQL representation.
/// </summary>
/// <param name="shapedQueryExpression">A <see cref="ShapedQueryExpression"/> on which the lambda expression is being applied.</param>
/// <param name="lambdaExpression">A <see cref="LambdaExpression"/> to translate into SQL.</param>
/// <returns>A <see cref="SqlExpression"/> which is translation of given lambda expression or <see langword="null"/>.</returns>
protected virtual SqlExpression? TranslateLambdaExpression(
ShapedQueryExpression shapedQueryExpression,
LambdaExpression lambdaExpression)
=> TranslateExpression(RemapLambdaBody(shapedQueryExpression, lambdaExpression));
Expand Down Expand Up @@ -1465,45 +1468,11 @@ private static Expression MatchShaperNullabilityForSetOperation(Expression shape
}
}

private SqlExpression? TranslateAverage(SqlExpression sqlExpression)
=> RelationalDependencies.AggregateMethodCallTranslatorProvider.Translate(
RelationalDependencies.Model, QueryableMethods.GetAverageWithoutSelector(sqlExpression.Type),
new EnumerableExpression(sqlExpression), Array.Empty<SqlExpression>(), _queryCompilationContext.Logger);

private SqlExpression? TranslateCount(SqlExpression sqlExpression)
=> RelationalDependencies.AggregateMethodCallTranslatorProvider.Translate(
RelationalDependencies.Model, QueryableMethods.CountWithoutPredicate,
new EnumerableExpression(sqlExpression), Array.Empty<SqlExpression>(), _queryCompilationContext.Logger);

private SqlExpression? TranslateLongCount(SqlExpression sqlExpression)
=> RelationalDependencies.AggregateMethodCallTranslatorProvider.Translate(
RelationalDependencies.Model, QueryableMethods.LongCountWithoutPredicate,
new EnumerableExpression(sqlExpression), Array.Empty<SqlExpression>(), _queryCompilationContext.Logger);

private SqlExpression? TranslateMax(SqlExpression sqlExpression)
=> RelationalDependencies.AggregateMethodCallTranslatorProvider.Translate(
RelationalDependencies.Model, QueryableMethods.MaxWithoutSelector,
new EnumerableExpression(sqlExpression), Array.Empty<SqlExpression>(), _queryCompilationContext.Logger);

private SqlExpression? TranslateMin(SqlExpression sqlExpression)
=> RelationalDependencies.AggregateMethodCallTranslatorProvider.Translate(
RelationalDependencies.Model, QueryableMethods.MinWithoutSelector,
new EnumerableExpression(sqlExpression), Array.Empty<SqlExpression>(), _queryCompilationContext.Logger);

private SqlExpression? TranslateSum(SqlExpression sqlExpression)
=> RelationalDependencies.AggregateMethodCallTranslatorProvider.Translate(
RelationalDependencies.Model, QueryableMethods.GetSumWithoutSelector(sqlExpression.Type),
new EnumerableExpression(sqlExpression), Array.Empty<SqlExpression>(), _queryCompilationContext.Logger);

private ShapedQueryExpression? TranslateAggregateWithPredicate(
ShapedQueryExpression source,
LambdaExpression? predicate,
Func<SqlExpression, SqlExpression?> aggregateTranslator,
Type resultType)
MethodInfo predicateLessMethodInfo)
{
var selectExpression = (SelectExpression)source.QueryExpression;
selectExpression.PrepareForAggregate();

if (predicate != null)
{
var translatedSource = TranslateWhere(source, predicate);
Expand All @@ -1515,9 +1484,19 @@ private static Expression MatchShaperNullabilityForSetOperation(Expression shape
source = translatedSource;
}

HandleGroupByForAggregate(selectExpression, eraseProjection: true);
var selectExpression = (SelectExpression)source.QueryExpression;
if (!selectExpression.IsDistinct)
{
selectExpression.ReplaceProjection(new List<Expression>());
}

var translation = aggregateTranslator(_sqlExpressionFactory.Fragment("*"));
selectExpression.PrepareForAggregate();
var selector = _sqlExpressionFactory.Fragment("*");
var methodCall = Expression.Call(
predicateLessMethodInfo.MakeGenericMethod(selector.Type),
Expression.Call(
QueryableMethods.AsQueryable.MakeGenericMethod(selector.Type), new EnumerableExpression(selector)));
var translation = TranslateExpression(methodCall);
if (translation == null)
{
return null;
Expand All @@ -1527,6 +1506,7 @@ private static Expression MatchShaperNullabilityForSetOperation(Expression shape

selectExpression.ClearOrdering();
selectExpression.ReplaceProjection(projectionMapping);
var resultType = predicateLessMethodInfo.ReturnType;

return source.UpdateShaperExpression(
Expression.Convert(
Expand All @@ -1536,18 +1516,17 @@ private static Expression MatchShaperNullabilityForSetOperation(Expression shape

private ShapedQueryExpression? TranslateAggregateWithSelector(
ShapedQueryExpression source,
LambdaExpression? selector,
Func<SqlExpression, SqlExpression?> aggregateTranslator,
LambdaExpression? selectorLambda,
Func<Type, MethodInfo> methodGenerator,
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bool throwWhenEmpty,
Type resultType)
{
var selectExpression = (SelectExpression)source.QueryExpression;
selectExpression.PrepareForAggregate();
HandleGroupByForAggregate(selectExpression);

SqlExpression translatedSelector;
if (selector == null
|| selector.Body == selector.Parameters[0])
Expression? selector = null;
if (selectorLambda == null
|| selectorLambda.Body == selectorLambda.Parameters[0])
{
var shaperExpression = source.ShaperExpression;
if (shaperExpression is UnaryExpression unaryExpression
Expand All @@ -1558,34 +1537,32 @@ private static Expression MatchShaperNullabilityForSetOperation(Expression shape

if (shaperExpression is ProjectionBindingExpression projectionBindingExpression)
{
translatedSelector = (SqlExpression)selectExpression.GetProjection(projectionBindingExpression);
}
else
{
return null;
selector = selectExpression.GetProjection(projectionBindingExpression);
}
}
else
{
var newSelector = RemapLambdaBody(source, selector);
if (TranslateExpression(newSelector) is SqlExpression sqlExpression)
{
translatedSelector = sqlExpression;
}
else
{
return null;
}
selector = RemapLambdaBody(source, selectorLambda);
}

if (selector == null
|| TranslateExpression(selector) is not SqlExpression translatedSelector)
{
return null;
}

var projection = aggregateTranslator(translatedSelector);
if (projection == null)
var methodCall = Expression.Call(
methodGenerator(translatedSelector.Type),
Expression.Call(
QueryableMethods.AsQueryable.MakeGenericMethod(translatedSelector.Type), new EnumerableExpression(translatedSelector)));
var translation = _sqlTranslator.Translate(methodCall);
if (translation == null)
{
return null;
}

selectExpression.ReplaceProjection(
new Dictionary<ProjectionMember, Expression> { { new ProjectionMember(), projection } });
new Dictionary<ProjectionMember, Expression> { { new ProjectionMember(), translation } });

selectExpression.ClearOrdering();
Expression shaper;
Expand All @@ -1602,7 +1579,7 @@ private static Expression MatchShaperNullabilityForSetOperation(Expression shape
var resultVariable = Expression.Variable(nullableResultType, "result");
var returnValueForNull = resultType.IsNullableType()
? (Expression)Expression.Constant(null, resultType)
: projection.Type.IsNullableType()
: translation.Type.IsNullableType()
? Expression.Default(resultType)
: Expression.Throw(
Expression.New(
Expand All @@ -1624,7 +1601,7 @@ private static Expression MatchShaperNullabilityForSetOperation(Expression shape
else
{
// Sum case. Projection is always non-null. We read nullable value.
shaper = new ProjectionBindingExpression(source.QueryExpression, new ProjectionMember(), projection.Type.MakeNullable());
shaper = new ProjectionBindingExpression(source.QueryExpression, new ProjectionMember(), translation.Type.MakeNullable());

if (resultType != shaper.Type)
{
Expand Down
16 changes: 1 addition & 15 deletions ...ore.Relational/Query/RelationalQueryableMethodTranslatingExpressionVisitorDependencies.cs
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Expand Up @@ -47,14 +47,10 @@ public sealed record RelationalQueryableMethodTranslatingExpressionVisitorDepend
[EntityFrameworkInternal]
public RelationalQueryableMethodTranslatingExpressionVisitorDependencies(
IRelationalSqlTranslatingExpressionVisitorFactory relationalSqlTranslatingExpressionVisitorFactory,
ISqlExpressionFactory sqlExpressionFactory,
IModel model,
IAggregateMethodCallTranslatorProvider aggregateMethodCallTranslatorProvider)
ISqlExpressionFactory sqlExpressionFactory)
{
RelationalSqlTranslatingExpressionVisitorFactory = relationalSqlTranslatingExpressionVisitorFactory;
SqlExpressionFactory = sqlExpressionFactory;
Model = model;
AggregateMethodCallTranslatorProvider = aggregateMethodCallTranslatorProvider;
}

/// <summary>
Expand All @@ -66,14 +62,4 @@ public RelationalQueryableMethodTranslatingExpressionVisitorDependencies(
/// The SQL expression factory.
/// </summary>
public ISqlExpressionFactory SqlExpressionFactory { get; init; }

/// <summary>
/// The model.
/// </summary>
public IModel Model { get; init; }

/// <summary>
/// The aggregate method-call translation provider.
/// </summary>
public IAggregateMethodCallTranslatorProvider AggregateMethodCallTranslatorProvider { get; }
}
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