EPAM Systems Interview Question

1) Difference Between OLAP and OLTP, Normalization and DeNor, Union and UnionAll, 2) SCD Types 3) ETL PIP line; We will get the data from Source CSV as Table data But we Need a Destination in CSV, No data loading In SQL Server . which transformation do you use? 4) How Will You do Optimization in SQL Querry and StoreProcedure.