How to do it...

1. Connect to Teradata Database using SQLA or Studio.
2. Execute the following query to get the result set:

/*OLAP select*/
SELECT EMP_ID,
SAL_Months,
sale_done,
sale_target,
min(sale_done)
OVER (
PARTITION BY EMP_ID ORDER BY 
SAL_Months ROWS 2 PRECEDING) FROM EMP_SAL;

1. The result set will have the minimum amount of sales from employees in 3 months.
2. The RANK and ORDER BY functions will be used to sort rows in ascending and descending order as shown in code.