Writing special linq query

Question

4.00/5 (1 vote)

See more:

Hi How can I write the followin tsql query by linq:

SQL

Select * From employees where EmployeeId not in(select EmployeeId from Orders)

Thanks

Posted 21-May-11 8:09am

Vahid Ghadiri

Updated 21-May-11 8:13am

Sandeep Mewara

v2

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Wonde Tadesse · Answer 1 · 2011-05-21T08:18:00

Solution 1

Generally you can use Linqer[^] to convert any SQL statement to LINQ.

[EDITED]

For your question the tsql will look like this.

C#

var query =
    from e in Employees
    where !(from o in Orders
            select o.EmployeeID)
           .Contains(e.EmployeeID)
    select e;

I hope this helps you well.

Posted 21-May-11 8:18am

Wonde Tadesse

Updated 21-May-11 15:52pm

v3

Comments

Wonde Tadesse 21-May-11 14:39pm

Can anyone tell me what is wrong with this answer ?

NuttingCDEF 22-May-11 9:36am

As far as I can see, not a lot - though there might be possible optimisations to make it run more efficiently. 2 suggestions below - I haven't tested them, so if they don't work, think about the concepts rather than the exact detail :-)

Suggestion 1 (run the Orders query once only and eliminate duplicates from the result)

var IDs = (from o in Orders
select o.EmployeeID).Distinct();

var query =
from e in Employees
where !(IDs.Contains(e.EmployeeID))
select e;

Suggestion 2 (relies on a relationship)

var query =
from e in Employees
where e.Orders.Count() == 0
select e;

Wonde Tadesse 22-May-11 10:34am

Thank you NuttingCDEF.