Problems with UNION

Problems with UNION

Postby dilbert » Mon 25 Jan 2010 12:26

I have encountered two problems with Union method.
I'm currently using dotConnect for MySQL 5.50.79.

1) It is possible only to select simple types - not whole entity. For example this query is evaluated correctly:
Code: Select all
(from t1 in DB.Orders
  where t1.Id == 1
  select t1.Id_product)
.Union(
from t1 in DB.Orders
where t1.Id == 2
select t1.Id_product).ToList();


In contrast to this one which throws NotSupportedException:
Code: Select all
(from t1 in DB.Orders
  where t1.Id == 1
  select t1.Products)
.Union(
from t1 in DB.Orders
where t1.Id == 2
select t1.Products).ToList();




2) NotSupportedException is also thrown if Distinct method is used right after a query with Union method:
Code: Select all
(query1).Union(query2).Distinct().ToList()


There is a workaround, however not effective:
Code: Select all
(query1).Union(query2).ToList().Distinct().ToList()
dilbert
 
Posts: 68
Joined: Tue 28 Apr 2009 10:11

Postby AndreyR » Tue 26 Jan 2010 17:29

These features are not implemented yet. We are investigating the possibility to add them.
I will let you know about the results of our investigation.
AndreyR
Devart Team
 
Posts: 2919
Joined: Mon 07 Jul 2008 13:16


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