Explain the Table Calculation Function ' LAST() ' in Tableau with Example?

In Tableau, the LAST() function is a table calculation function that returns the value of a dimension or measure for the last row within a specified context or partition. The LAST() function is typically used to retrieve the final value in a sorted order or the last value within a partition.

The syntax for the LAST() function in Tableau is as follows:

LAST(expression, [start], [end])

• expression: The field or calculation for which you want to retrieve the last value.
• start (optional): Specifies the starting point of the partition or order. If not specified, the partition starts from the first row in the partition.
• end (optional): Specifies the ending point of the partition or order. If not specified, the partition ends at the current row.

Here's an example to demonstrate how to use the LAST() function in Tableau:

Suppose you have a dataset that contains information about monthly sales for different regions. You want to retrieve the last month's sales for each region to analyze the recent performance.

1. Open Tableau and connect to your dataset.
2. Drag the "Region" field to the Rows shelf to create a table view with regions.
3. Drag the "Month" field to the Columns shelf to display months horizontally.
4. Drag the "Sales" field to the Marks card to apply the aggregation. By default, Tableau will aggregate the sales using the SUM function.
5. Right-click on the "Sales" field in the Marks card and select "Add Table Calculation."
6. In the calculation dialog box, choose "LAST" from the list of table calculation functions.
7. Configure the specific settings for the LAST function, such as the addressing and partitioning options.
8. Click "OK" to apply the LAST function to the sales values.

Tableau will display the last month's sales for each region based on the applied table calculation. You can further customize the view, apply sorting, or add additional calculations based on the last value.

The LAST function is useful when you want to analyze or compare the final value within a specific context, such as the last value in a sorted order, the last value within a partition, or the last value based on a specific condition.

By leveraging the LAST function in Tableau, you can gain insights into the recent performance or occurrence of a dimension or measure within your dataset.