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Tuesday, March 12, 2013
SQL Server–Find Nth Largest/smallest entry in a table

We could find the maximum and minimum value in a table by using the SQL inbuilt aggregate functions MAX() and MIN() respectively. But, many times there comes a scenario when we need to find the second or third largest/smallest entry in table. There is no built-in SQL function to get this information but we can use Row_Number() function to our advantage to find Nth Largest or smallest value in table.

For example – usually, to find maximum value we normally use the following

select MAX(column_name) as column_name from table_name 

This is equivalent to the following

SELECT * FROM
(
SELECT ROW_NUMBER() OVER ( ORDER BY column_name DESC) ROW_NUM, column_name FROM table_name
)  T 
WHERE row_num = 1
However, this can then be used to get any largest value in the table, all you have to do is just change the row_num value in the where clause.
So, to get the second largest value set 
WHERE row_num = 2

Similarly to find the second smallest entry, just sort the column by ascending and set the where clause to 2.

Hope this helps!

Posted On Tuesday, March 12, 2013 3:45 PM | Comments (2)