Return null from Min/Max/Average when nullable type and no rows

Fixes #16542
dotnet · Aug 6, 2019 · 8ba9f17 · 8ba9f17
1 parent a401a94
commit 8ba9f17
Show file tree

Hide file tree

Showing 4 changed files with 227 additions and 220 deletions.
diff --git a/src/EFCore.Relational/Query/RelationalQueryableMethodTranslatingExpressionVisitor.cs b/src/EFCore.Relational/Query/RelationalQueryableMethodTranslatingExpressionVisitor.cs
@@ -1096,7 +1096,22 @@ private ShapedQueryExpression AggregateResultShaper(
 
  Expression shaper = new ProjectionBindingExpression(source.QueryExpression, new ProjectionMember(), projection.Type);
 
- if (throwOnNullResult)
+ if (throwOnNullResult
+ && resultType.IsNullableType())
+ {
+ var resultVariable = Expression.Variable(projection.Type, "result");
+
+ shaper = Expression.Block(
+ new[] { resultVariable },
+ Expression.Assign(resultVariable, shaper),
+ Expression.Condition(
+ Expression.Equal(resultVariable, Expression.Default(projection.Type)),
+ Expression.Constant(null, resultType),
+ resultType != resultVariable.Type
+ ? Expression.Convert(resultVariable, resultType)
+ : (Expression)resultVariable));
+ }
+ else if (throwOnNullResult)
  {
  var resultVariable = Expression.Variable(projection.Type, "result");