Tableau's Order of Operations, often referred to as the "Order of Operations for Visualization," is a set of rules and guidelines that dictate the sequence in which Tableau performs calculations and processes data when you create a visualization or worksheet. Following this order is essential for understanding how Tableau computes and displays the results of your analysis accurately.
Source: Tableau official webpage
Here is a simplified explanation of Tableau's Order of Operations:
Data Source: The process begins with your data source. Tableau connects to your data and retrieves the necessary information.
Extract Filters: If you are working with an extract (Tableau Data Extract or TDE), any filters applied to the extract are applied at this stage. Extracts are pre-aggregated subsets of your data, and applying filters here reduces the data used in your analysis.
Data Source Filters: Next, Tableau applies data source filters. These filters limit the data that is brought into Tableau for analysis. Data source filters can be set at the data connection level and apply to all worksheets and dashboards using that data source.
Context Filters: If you've defined any context filters in your worksheet, they are applied at this stage. Context filters are used to create a temporary subset of data for more complex filtering.
Top N and Dimension Filters: Filters like "Top N" or filters based on dimensions (e.g., selecting specific categories) are applied to further reduce the data displayed in your visualization.
Compute Using and Addressing: If you have calculated fields or table calculations that involve specific computations within a partition (Compute Using) or across dimensions (Addressing), these calculations are performed at this stage.
Aggregation: Aggregation functions, such as SUM, AVG, MIN, and MAX, are applied to measure values based on the dimensions included in your visualization. This step involves summarizing the data to display in the view.
Filters and Actions: Any additional filters or actions you've applied to your worksheet are executed at this point. Filters can be applied to the entire worksheet or specific sheets, and actions can be used for interactivity between sheets.
Source: Tableau official website
Row-Level Calculations: If you have defined any row-level calculations, such as calculated fields or level of detail (LOD) expressions, they are evaluated and applied.
Grand Totals and Subtotals: Finally, Tableau calculates and displays grand totals and subtotals based on the aggregation functions and dimensions used in your visualization.
Understanding the Order of Operations is crucial when designing complex visualizations or creating calculated fields in Tableau. It helps you ensure that your analysis is accurate and that the right filters, calculations, and aggregations are applied in the correct sequence to achieve your desired results.
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