Important notes in Tableau Desktop

Important notes in Tableau Desktop

• Multidimensional data sources do not support aggregations and binned data.
• Multidimensional data sources supports only in windows.
• You can use tableau to aggregate measures only with relational data sources, multidimensional data sources contain aggregated data only.
• Null values are ignored in median, count, sum, avg and countD.
• Median does not work on live connection.
• Median was not there before 8.2 version.
• Percentile required extract data. Percentile works with only extracts.
• When all measures are disaggregated you see a mark for each row in the view, you can't select marks to keep only, exclude or create a set when all measures are disaggregated.
• A dimension can be aggregated as a measure using minimum, maximum, count and count (distinct)
• Count (Distinct) is not support for Microsoft Access, Microsoft Excel and text files data sources. These data sources requires extract to work with CountD
• Dis-aggregating the data can result in a performance degradation.
• When you are writing formulas, any part that displays in bold indicates that it will be computed locally with in tableau on the aggregated results. Any normal weight text will be computed at the database level.
• Functions are displayed in Blue color while creating calculation field.
• Data window fields are displayed in Orange color while creating calculation field.
• Operators are displayed as Blank color while creating calculation field.
• Parameters are displayed as Purple color while creating calculation field.
• Comments are colored as Green color while creating calculation field.
• Grand Totals cannot be applied to continuous dimensions.
• The view must have at least one header to apply Grand Totals.
• If row headers are displayed you can calculate Grand Total for row, If column headers are displayed you can calculate Grand Total for column.
• Forecasting is not supported for multidimensional data sources.
• Forecasting doesn’t work if the view contains:
  (a) Table calculations
  (b) Disaggregated measures
  (c) Percent calculations
  (d) Grand Totals or Sub Totals
  (e) Date values with aggregation set to exact date
  (f) A time series contains null values also imposes constraints.
• The smaller the p-value, the more significant the model.
• If your data contains negative values tableau cannot plot them on a logarithmic scale. All values with a negative value will be displayed at 1 on the axis.
• The pattern match is not case sensitive in filters wild card match.
• If we are using multidimensional data source wild card match option is only available when filtering single level hierarchies and attributes.
• Filters cannot be applied across multiple data sources.
• In previous versions of tableau desktop, the All using this data source option was called make global and the only this worksheet option was make local.
• Sorted fields are identified by a sort icon on the right side of the field.
• You cannot nest inner joins within left or right joins. These joins will cause a "join expression not supported" error.

Source : Suresh Reddy NallapaReddy