Generating a distinct set of values for a column involves a large amount of comparison operations. The Distinct tab excludes text columns because comparing large amounts of unstructured text to determine whether two values are equal is not a simple operation. There are two primary reasons why:

If you need to compare text values, consider using a Derive node to capture a subset of the text (e.g. the first 200 characters) in a new String column. PolyAnalyst can then easily compare the String values to one another. Another avenue to consider is to use a Distinct Texts node.

You can sort the column list by the data type or name. To sort the list, right click on the Name column header and select the desired sort option (e.g. Sort ascending/descending) from the right-click menu.

By default, the list is sorted in natural order, the order of the columns as stored in the dataset. You can return to using the natural order (after having chosen to sort by another order) by selecting the appropriate option in the right-click menu for the Name column header.

The total number of distinct values for the column is displayed in the navigation bar area of this right list (usually at the bottom, if visible). If the navigation bar is not visible, click the Toggle navigation bar button on the toolbar at the top of this window.

You can also view the number of distinct values for a column from the output of the Statistics tab (in the Distinct property of a column), which is sometimes a simpler and faster method than using the Distinct tab. In contrast, the Distinct tab is better utilized when you want to view specific counts of different distinct values.

You can search the list of distinct values similar to how you search the values of a column in the data viewer. See the topic on searching for values using the data viewer for more information.

You can export the list of distinct values for a column to a file, similar to how a dataset is exported. See the topics on exporting data for more information.

The Distinct tab is provided primarily for quick access to distinct values for smaller datasets. When you first decide to view the distinct values, PolyAnalyst calculates the number of distinct values for each column in the dataset. This operation works column by column (in natural column order), and can sometimes take several seconds, minutes, or even hours when working with a very large number of columns. During the time this calculation occurs, a progress bar is displayed on the screen.

When you click on a column to view its distinct values, a similar operation occurs where PolyAnalyst determines the different values in the column and the count for each distinct value. During this time a progress bar is displayed on the screen. This operation can take a considerable amount of time when working with a very large dataset (e.g. several million records).

When working with larger data sets, consider using the Distinct node as an alternative to using the Distinct tab. The Distinct node is more efficient and scales very well for working with very large data sets.

You can recreate a dataset that is similar to the output of the Distinct tab using the Aggregate node (not to be confused with Aggregate Values). The Aggregate node is located in the Table Operations branch of the node palette.