MySQL Bugs: #51475: Entity Framework - OrderBy Statement SQL Translation Failure

Bug #51475	Entity Framework - OrderBy Statement SQL Translation Failure
Submitted:	24 Feb 2010 20:45	Modified:	25 Mar 2010 8:21
Reporter:	Nathan Taylor	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	Connector / NET	Severity:	S2 (Serious)
Version:	6.2.2	OS:	Any
Assigned to:	Assigned Account	CPU Architecture:	Any
Tags:	entity-framework, orderby

Description:
I currently have a table structure defined in one of my applications where there is a column for a given table called "Order" which is a nullable integer used to sort the results returned within the application. The intended behavior is to have all non-null values appear first in the correct order, followed sequentially by all null values. To do this the following statement was used:

var list = EntityCollection.OrderBy(e => e.Order ?? int.Max);

However, running the above statement produces the following exception:

ArgumentException: A valid ResultType could not be inferred from the ResultTypes of the specified 'Then' expressions.

I also attempted to do:

var list = EntityCollection.OrderBy(e => e.Order.HasValue ? e.Order.Value : int.Max);

Which compiled, but did not affect the default ordering of the collection in any way. Likewise with the same expression applied to OrderByDescending().

The only way I was able to make this work was by executing the query with .ToList() and then executing the OrderBy at that point. Naturally, this is not especially desirable.

How to repeat:
Create a table entity with a nullable value.
Attempt to sort the table data by that nullable value using a LINQ to Entities Expression: EntityCollection.OrderBy(e => e.Order ?? int.Max);

Hi Nathan and thanks for your report.

It would be very very nice to attach DDL/DML statements used, a part of general query log showing what actually got to MySQL server and a sample project file showing the problem between what you expected and what you actually got.
I don't think me guessing what would all that be is a viable choice...

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".