# Classified Columns (Data Mining)

**Applies to:**
SQL Server 2019 and earlier Analysis Services
Azure Analysis Services
Power BI Premium

Important

Data mining was deprecated in SQL Server 2017 Analysis Services and now discontinued in SQL Server 2022 Analysis Services. Documentation is not updated for deprecated and discontinued features. To learn more, see Analysis Services backward compatibility.

When you define a classified column, you create a relationship between the current column and another column in the mining structure. The data in the mining structure column that you designate as the classified column contains categorical information that describes the values in another column in the mining structure.

For example, suppose you have two columns with numerical data: one column, [Yearly Purchases], contains the total yearly purchases per customer for a specific calendar year, and the other column, [Standard Deviations], contains the standard deviations for those values. In this case you could designate the [Yearly Purchases] column as the classified column, and the model would be able to use this relationship in analysis.

Note

The algorithms provided in SQL Server Analysis Services do not support the use of classified columns; this feature is provided for use in creating custom algorithms.

## Defining a Classified Column

The data type of a classified column must be either **Long** or **Double**.

The following list describes the content types that SQL Server Analysis Services supports for classified columns.

**PROBABILITY**

The value in the column is the probability of the associated value, and is a number between 0 and 1.

**VARIANCE**

The value in the column is the variance of the associated value.

**STDEV**

The value in the column is the standard deviation of the associated value.

**PROBABILITY_VARIANCE**

The value in the column is the variance of the probability for the associated value.

**PROBABILITY_STDEV**

The value in the column is the standard deviation of the probability for the associated value.

**SUPPORT**

The value in the column is the weight, or case replication factor, of the associated value.

## See Also

Content Types (Data Mining)

Mining Structures (Analysis Services - Data Mining)

Data Types (Data Mining)