NHibernate RowCount in LINQ produces SQL Exception

I have a query where I am only interested in the row count, however the query that NHibernate produces does not work with Sybase. I already have a custom Sybase dialect, but I can't find where to override the rowcount.

Given the following code:

var a = from b in table where b.something = 5 select b
var rows = a.Count

Generates an SQL similar to this:

select cast(count(*) as INTEGER) as p1 from table

I don't get why NHibernate wants to cast the count result, nor how I can override the dialect or elsewhere so NHibernate doesn't include the cast. The result of a count is castable to integer anyways.

If I however use QueryOver, things work perfectly. The problem then however, is that one off my conditions is dependent on the length of a string (yes, the db design could be better, but I can currently not change it). Using linq to call .Length on a string in the conditions work. However I can't use the string length as a condition in the QueryOver expressions. I also need a contains operation, which works with linq, but not QueryOver.

Is there a way to override how the Count query is generated, 开发者_开发技巧so it will work? I am only interested if there is any rows matching, not the count, is there a different way of doing that? Can instead the QueryOver? interface to use the SQL length and in operators?

You can understand if there are any rows matching by using Any function like this:

var a = from b in table where b.something = 5 select b; 
var isMatch = a.Any();