How to get max id from shift_details (table) in SQL server in WPF C#

Based on the SQL you have posted it looks as if you are trying to get closing_date and employee_id from shift details for the row containing the maximum sd_id.

There are many ways you can achieve this

1. Declare a variable, assign the max sd_id value to it and select from the table for that id e.g.

declare @maxid int = (SELECT MAX(sd_id) AS sd_id FROM shift_details);
Select closing_date,employee_id from shift_details 
where sd_id = @maxid;

2. Use a sub-query to get that value and filter the results on that sub-query e.g.

Select closing_date,employee_id from shift_details 
where sd_id = (SELECT MAX(sd_id) from shift_details);

3. Do an inner join on a sub-query e.g.

Select closing_date,employee_id from shift_details a
inner join (SELECT MAX(sd_id) as maxid from shift_details) b on a.sd_id = b.maxid;

4. Use a combination of ORDER BY and TOP (N.B. This is not a recommended approach, look at the execution plans if you want to see why. I'm only including it here for illustrative purposes.) e.g.

Select top 1 closing_date,employee_id from shift_details order by sd_id desc;

If this is not what you were trying to do then update your question with more information, and reply to this post and I will try to help you