Exploring and Analyzing Data37% of the exam
Calculated fields and when to use parameters
Write string, date and arithmetic calculated fields in the calculation editor (+ for concatenation, STR, DATEADD, DATEDIFF, DATEPART), know how a new calculated field lands in the Data pane, and decide when a parameter, a single workbook-wide value used in calculations, filters and reference lines, fits a requirement.
Apply analytics to a worksheet: Add a manual or a computed sort; Add a reference line; Use a quick table calculation; Use bins and histograms; Create a calculated field (for example, string, date, simple arithmetic); Explain when to use a parameter; Display totals on a worksheet.
~8 min read · 6 practice questions ·
What the exam expects
- Create a calculated field from Analysis > Create Calculated Field and predict where it appears in the Data pane and how it aggregates.
- Write simple string calculations, converting numbers with STR before concatenating with +.
- Write date calculations with DATEADD, DATEDIFF and DATEPART and tell their return types apart.
- Write simple arithmetic calculations between measures.
- Explain when to use a parameter: a viewer-controlled value used in a calculation, a Top N filter or a reference line; create it, show its control, and know what deleting it breaks.
Key terms:
- Calculated field: a new field whose values come from a formula you write; saved to the Tableau data source, leaving the original data untouched.
- Calculation editor: the dialog where you name a calculated field and type its formula.
- Type conversion (casting): changing a value's data type inside a formula, such as STR to make a string.
- Parameter: a workbook variable, such as a number, date or string, that can replace a constant value in a calculation, filter or reference line.
- Parameter control: the worksheet card that lets viewers change a parameter's value.
Key facts
Create a calculated field
- Detail
- Analysis > Create Calculated Field
Numeric calculated field
- Detail
- Added to the Data pane as a measure
Calculated field icon
- Detail
- Equal sign (=) next to the data type icon
Default aggregation in a view
- Detail
- Automatically aggregated as a sum
Source data
- Detail
- Original data remains untouched
+ operator
- Detail
- Adds numbers, concatenates strings
STR
- Detail
- Casts its argument as a string
DATEADD vs DATEDIFF
- Detail
- Returns a date vs returns an integer count
Parameter uses
- Detail
- Calculations, filters, reference lines
Parameter scope
- Detail
- Global across the workbook
Deleting a parameter
- Detail
- Calculated fields that use it become invalid
Sources for this section (5)
- Get Started with Calculations in Tableauhelp.tableau.com (opens in a new tab)
- Writing Calculations in Tableauhelp.tableau.com (opens in a new tab)
- Type Conversionhelp.tableau.com (opens in a new tab)
- Date Functionshelp.tableau.com (opens in a new tab)
- Create Parametershelp.tableau.com (opens in a new tab)
- What three values must you specify when a parameter's allowable values are a Range?
- When can't a parameter use Range for its allowable values?
- Which date function returns an integer count of days between two dates?
- Why don't you re-add a calculated field to its view after editing its formula?
The questions are free to read. Answers with their sources and self-grading are included with the pack.
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