Query Question in SQL

1. Find nth salary form Employee:

TO FIND NTH HIGHEST SALARY USING CTE

1. SELECT*FROM  [DBO].[EMPLOYEE] ORDER BY SALARY DESC  
2. GO  
3.   
4. WITH RESULT AS  
5. (  
6.     SELECT SALARY,  
7.            DENSE_RANK() OVER (ORDER BY SALARY DESC) AS DENSERANK  
8.     FROM EMPLOYEE  
9. )  
10. SELECT TOP 1 SALARY  
11. FROM RESULT  
12. WHERE DENSERANK = 3  

duplicate records

SELECT username, email, COUNT(*)
FROM users
GROUP BY username, email
HAVING COUNT(*) > 1

If you want to delete the duplicates, here's a much simpler way to do it than having to find even/odd rows into a triple sub-select:

SELECT id, name, email 
FROM users u, users u2
WHERE u.name = u2.name AND u.email = u2.email AND u.id > u2.id

And so to delete:

DELETE FROM users
WHERE id IN (
    SELECT id/*, name, email*/
    FROM users u, users u2
    WHERE u.name = u2.name AND u.email = u2.email AND u.id > u2.id
)

If you want to delete duplicate record with contains one record.

with TEST as(
 select ProductId,city, ROW_NUMBER()  OVER(PARTITION BY city ORDER BY city) AS T from PRODUCTDETAILS
)
SELECT * FROM TEST WHERE T>1