What is the purpose of using unpivot in Oracle?

In Oracle, the UNPIVOT operation is used to transform row data into column data. Its purpose is to convert columns in a table into rows, and to create a new column for each converted row to identify the value of the original column.

Specifically, the UNPIVOT operation can be used to perform the following tasks:

1. Reverse data structure: transforming columns with similar features (e.g., sales data for different months) into a single column with values.
2. Data analysis and report generation: converting column data into rows for easier data analysis and report generation.
3. Data querying and filtering can be made more convenient by transforming column data into row data, enabling easier use of the WHERE clause.

In conclusion, the UNPIVOT operation can assist us in conveniently processing and analyzing data when we need to convert column data into row data in a table.