Hello I am beginner in TD. I came across a term called OLAP function. So just wanted to know can anyone throw some light on this.
what are olap functions ? how they differ from aggregate functions?
Ordered Analytical Functions (sometimes called OLAP functions) operate over an ordered set of rows and/or results depend on the previous row.
Examples include RANK or running SUM (also referred to as a windowed aggregate function).
OLAP functions are most used for order analytical and data mining purpose, where order of row matters. For example: to calculate running sum of inventory.
OLAP functions allows us to fetch the value for a PK combination by ordering them and choosing the desired value. We can take the previous value as well as the succeding value using this.