In SQL server, TOP is returning unexpected rows.

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Hi, I'm having a table of Employees. It has EmployeeName (varchar(100)) and Salary field (deciaml). All the records are in sorted order, and I was trying to fetch records from 11th Employee to 20 Employee. I know there are multiple and simple ways to get this data and I've also done it with 3-4 different ways. But, one of the way that I tried is not working and it retruns unexpected data. Below are the scripts that I'm using:

Data script:

declare @counter int = 1
while(@counter <= 50)
begin
	insert into Employee (name,salary) 	select CONCAT('name - ',@counter),100*@counter;
	set @counter += 1;
end

Select * from Employee

Query to fetch records:

select top(10) * from (
Select Top(20)* from Employee
) as t order by t.id desc

Explanation: First, I'm getting records of first 20 employees, using TOP(20). Then, I'm trying to order the data of 20 Employee in descending order and then get TOP(10) employees. It supposed ot return me Employee from 11-20 (in any order descinduing or ascinding). But, it returns employees from 50-41. Why?

What I have tried:

I've tried on google, all are talking about Views and TOP but in my case there is no View.

Posted 3-Sep-16 3:25am

sunil kumar meena

Updated 3-Sep-16 9:00am

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OriginalGriff · Accepted Answer · 2016-09-03T04:07:00

Probably, because you don't specify an ORDER BY condition on the idder set: so SQL is at liberty to return rows in any order it finds suitable. You then take the top 20 of those, order them by ID, and select the top 10 of that result.
If you want to extract specific rows with TOP, you always need to specify an ORDER BY or you have no real control over what rows are returned.

sunil kumar meena · Accepted Answer · 2016-09-03T09:00:00

Solution 2

select top(10) e.*
from (Select Top(20) e.*
      from Employee e
      order by e.id 
     ) e
order by e.id desc;

This is the final query that returns expected result. Thanks to @OriginalGriff for pointing out the problem in query.

Posted 3-Sep-16 9:00am