What is Unpivot?

Unpivot is a software tool used in data analytics, specifically as a SQL function, to transform data originally organized in columns into rows. This process enhances the usability and management of the data, making it more accessible for analysis and reporting purposes. As a reporting tool function, the Unpivot operation is instrumental in reorienting data to facilitate various analytical tasks.

As a service, UNPIVOT offers unique functionalities that are distinct from the PIVOT operation. It does not serve to exactly reverse the PIVOT function, nor does it reproduce the original table-valued expression. One of the features of the UNPIVOT service is its ability to potentially remove null values from the input, which it achieves by merging rows where null values are present.

When using UNPIVOT, it is often necessary to convert all values to a uniform data type, such as varchar, due to its nature as a SQL function. This is because UNPIVOT is not inherently a database function but rather a function employed within reporting tools. After the UNPIVOT operation is complete, there may be a requirement to convert the values back to their original data types, which is another step in the data preparation process for reporting and analysis.