Horizontal Aggregations in SQL to Prepare Data Sets Using PIVOT Operator
Preparing dataset is a very difficult process in cases where it has to be given as input for data mining which involves complex queries, joining tables, and aggregating columns. Existing SQL aggregations have limitations to prepare data sets because they return one column per aggregated group. The authors' project aims at implementing a new class of functions called horizontal aggregation. Horizontal aggregation build data set with a horizontal de-normalized layout, which is the standard layout required by most data mining algorithms. PIVOT operator, offered by RDBMS is used to calculate aggregate operations.