Using Calculations


1. Working with Strings and Type Conversion Functions

Concatenate string fields

To concatenate strings means to add them together

  • Use “+” operator to connect strings

    image-20210528101257676

  • For fields with other data types, use type conversion function “STR()” to change them into strings

    image-20210528102740095


2. Working with Dates

Using Date-specific Calculations

[Tableau Help] – Date Functions

[Example - DATEDIFF]

DATEDIFF: Returns the difference between two dates. The difference is expressed in units of date_part

image-20210528104621973

3. Working with Aggregations

When dragging [measure] fields into the view, Tableau automatically aggregates [measure] to the lowest level of detail in the view.


Calculated Field Bring into the view Order of Operations
image-20210528123951612 image-20210528124107136 1. calculate the ratio for each row
2. sum the results of those ratios
image-20210528124605478 image-20210528124624680 1. sum the Profit values and Sales values
2. divide two totals and calculate the ratio

* When you pre-define aggregation in a calculated field, Tableau won’t perform further aggregation when you bring the field into the view. Instead, Tableau adds an “AGG” at the start of the field to indicate that the aggregation was pre-defined in the calculation.


[calculation without aggregation] VS [calculation including aggregation]

calculation without aggregation calculation including aggregation
Example image-20210528123951612 image-20210528124605478
Level of Detail 1. first performed at the row-level detail
2. then aggregated and brought into the view		 the result will be at the level of detail in the view
Brought into
the view		 perform aggregation automatically further aggregation can’t be performed