linq to entities
Showing posts with label linq to entities. Show all posts
Showing posts with label linq to entities. Show all posts

Error 25 The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'Join'

Udemy
I had a scenario where i needed to fetch Result Data from multiple tables on basis of some condition by applying joins between the tables using Entity Framework. I was using Linq queries as in EF linq query is faster than the normal string queries and stored procedures, but i was getting the exception.

Here is the query which i wrote:

I made the object of my EntitiesClass generated by EDM:


OLSContainer ols = new OLSContainer();
        var reSet = from l in ols.LEVEL_COURSE
                    join lp in ols.PACKAGES 
                    on new { l.course_ID, l.levelID } 
                    equals new { lp.course_ID, lp.level_ID }
                    select l;
which i know was wrong and on this query i was getting this exception:

Error 25 The type of one of the expressions in the join clause is 
incorrect. Type inference failed in the call to 'Join'

The mistake i was making was pretty was pretty simple in this scenario i dont need the join because i was only selecting data from LEVEL_COURSE table which can be achieved by simple where clause in the current scenario like this:



OLSContainer ols = new OLSContainer();
        var reSet = (from l in ols.LEVEL_COURSE
                    from p in ols.PACKAGES
                    where l.course_ID == p.course_ID 
                    && l.levelID == p.level_ID 
                    &&    l.course_ID==courseID
                    select new { l.levelID, l.levelName }).Distinct();

This solved my problem and the exception that i was getting was due to column names were same. My  PACKAGES table and LEVEL_COURSE table both have column named course_ID which were of same datat type as well so it was confusing compiler to take which one, but at last i got working thing as i needed.


Reference Link:

http://stackoverflow.com/questions/14273879/error25the-type-of-one-of-the-expressions-in-the-join-clause-is-incorrect-typ/14290833#14290833

Read More
Subscribe to: Posts (Atom)