LOD with date dimensions in Tableau - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does LOD stand for in Tableau?

LOD stands for Level of Detail. It lets you control the granularity of calculations independently from the view.

intermediate

How does a FIXED LOD expression work with date dimensions?

A FIXED LOD expression calculates a value at the exact date level you specify, ignoring filters on that dimension but not all filters or view level changes.

beginner

Example: What does this LOD expression do? { FIXED [Order Date] : SUM([Sales]) }

It calculates total sales for each unique order date, regardless of other dimensions in the view.

intermediate

Why use LOD with date dimensions instead of just using date in the view?

LOD lets you fix calculations at a specific date level even if you change the view to months or years, ensuring consistent results.

advanced

What is the difference between INCLUDE and EXCLUDE LOD with dates?

INCLUDE adds a finer date level to the calculation, while EXCLUDE removes a date level from the calculation granularity.

What does { FIXED [Order Date] : SUM([Sales]) } do in Tableau?

A Calculates average sales per customer

B Calculates sales for each order date ignoring other dimensions

C Filters sales by the current view's date level

D Calculates total sales for the entire dataset

The FIXED LOD fixes the calculation at the Order Date level, ignoring other dimensions.

Which LOD expression would you use to add a finer date level to your calculation?

A INCLUDE

B FIXED

C EXCLUDE

D FILTER

INCLUDE adds a finer level of detail, such as a more granular date level.

If you want to ignore filters on date in your calculation, which LOD keyword helps you?

A FIXED

B INCLUDE

C EXCLUDE

D AGGREGATE

FIXED LOD expressions ignore filters on the specified dimension.

What happens if you use EXCLUDE [Order Date] in an LOD expression?

A It filters data by Order Date

B It adds Order Date to the calculation granularity

C It fixes the calculation at Order Date level

D It removes the Order Date level from the calculation granularity

EXCLUDE removes the specified dimension from the calculation level.

Why is LOD useful with date dimensions in Tableau?

A To change date formats

B To sort dates alphabetically

C To create calculations independent of the view's date level

D To filter dates by year only

LOD allows calculations fixed at a date level regardless of how the view groups dates.

Explain how FIXED LOD expressions work with date dimensions in Tableau.

Think about how you can calculate sales per day even if the view shows months.

Describe the difference between INCLUDE and EXCLUDE LOD expressions when used with dates.

Consider how you want to adjust the detail level of your calculation.

Practice

1. What does a FIXED LOD expression with DATETRUNC('month', [Order Date]) do in Tableau?

easy

A. Calculates a value fixed at the month level, ignoring view filters on date.

B. Calculates a value that changes with every day in the month.

C. Filters data to only show the first day of each month.

D. Aggregates data by year instead of month.

Solution

1. Step 1: Understand FIXED LOD with DATETRUNC

   FIXED LOD fixes calculation at the specified date granularity, here month.

2. Step 2: Effect on calculation

   It ignores filters on date and calculates once per month, not per day.

3. Final Answer:

   Calculates a value fixed at the month level, ignoring view filters on date. -> Option A

4. Quick Check:

   LOD with DATETRUNC('month') fixes by month [OK]

Hint: FIXED + DATETRUNC fixes calculation at chosen date level [OK]

Common Mistakes:

• Thinking it filters data instead of fixing calculation
• Confusing month with day granularity
• Assuming it aggregates by year

2. Which of the following is the correct syntax for a FIXED LOD expression to calculate total sales by quarter in Tableau?

easy

A. {FIXED [DATETRUNC('quarter', [Order Date])] : SUM([Sales])}

B. {FIXED [Order Date], DATETRUNC('quarter') : SUM([Sales])}

C. {FIXED DATETRUNC('quarter', [Order Date]) : SUM(Sales)}

D. {FIXED DATETRUNC('quarter', [Order Date]) : SUM([Sales])}

Solution

1. Step 1: Check FIXED LOD syntax

   Correct syntax is {FIXED [dimension] : aggregation} where dimension can be an expression like DATETRUNC.

2. Step 2: Validate each option

   {FIXED DATETRUNC('quarter', [Order Date]) : SUM([Sales])} correctly uses {FIXED DATETRUNC('quarter', [Order Date]) : SUM([Sales])} with proper brackets and field names.

3. Final Answer:

   {FIXED DATETRUNC('quarter', [Order Date]) : SUM([Sales])} -> Option D

4. Quick Check:

   Correct FIXED LOD syntax uses brackets and field names [OK]

Hint: Use curly braces and brackets correctly in FIXED LOD [OK]

Common Mistakes:

• Missing brackets around field names
• Incorrect placement of DATETRUNC
• Using aggregation inside DATETRUNC

3. Given the FIXED LOD expression {FIXED DATETRUNC('year', [Order Date]) : SUM([Sales])}, what will be the result if the view shows data by month for 2023 with monthly sales as [1000, 1500, 1200]?

medium

A. [1000, 1500, 1200]

B. [3700, 3700, 3700]

C. [1233, 1233, 1233]

D. [0, 0, 0]

Solution

1. Step 1: Calculate yearly total sales

   Sum monthly sales: 1000 + 1500 + 1200 = 3700 for the year 2023.

2. Step 2: Apply FIXED LOD at year level

   LOD fixes total sales at year level, so each month shows 3700 regardless of monthly values.

3. Final Answer:

   [3700, 3700, 3700] -> Option B

4. Quick Check:

   Year-level FIXED LOD repeats yearly total per month [OK]

Hint: LOD FIXED at year repeats yearly total for all months [OK]

Common Mistakes:

• Assuming monthly sums instead of yearly total
• Adding averages instead of sums
• Confusing FIXED with INCLUDE or EXCLUDE

4. You wrote this LOD expression: {FIXED [DATETRUNC('month', [Order Date])] : SUM([Sales])} but Tableau shows an error. What is the likely problem?

medium

A. DATETRUNC cannot be used inside FIXED LOD expressions.

B. DATETRUNC should be wrapped in square brackets as a field.

C. Unnecessary square brackets around the DATETRUNC expression.

D. DATETRUNC expression must be inside parentheses, not brackets.

Solution

1. Step 1: Check syntax for FIXED LOD with expressions

   When using an expression like DATETRUNC inside FIXED, it must NOT be enclosed in square brackets to be treated as a dimension (brackets are only for field names).

2. Step 2: Identify the bracket issue

   The expression has unnecessary square brackets around DATETRUNC('month', [Order Date]), causing syntax error.

3. Final Answer:

   Unnecessary square brackets around the DATETRUNC expression. -> Option C

4. Quick Check:

   Expressions in FIXED must not be bracketed [OK]

Hint: Bracket expressions inside FIXED LOD properly [OK]

Common Mistakes:

• Putting brackets around DATETRUNC inside FIXED
• Confusing parentheses and brackets
• Assuming DATETRUNC is a field, not a function

5. You want to compare monthly sales to the total sales of the year for each month in Tableau. Which LOD expression correctly calculates the yearly total sales fixed by year to use in this comparison?

hard

A. {FIXED DATETRUNC('year', [Order Date]) : SUM([Sales])}

B. {FIXED [YEAR([Order Date])] : SUM([Sales])}

C. {INCLUDE DATETRUNC('year', [Order Date]) : SUM([Sales])}

D. {EXCLUDE DATETRUNC('month', [Order Date]) : SUM([Sales])}

Solution

1. Step 1: Identify correct date truncation for year

   DATETRUNC('year', [Order Date]) returns the first day of the year, suitable for fixing yearly level.

2. Step 2: Use FIXED LOD for consistent yearly total

   FIXED LOD with DATETRUNC('year', [Order Date]) fixes sales at year level, ignoring view filters.

3. Step 3: Compare monthly sales to yearly total

   This expression allows comparing each month's sales to the fixed yearly total.

4. Final Answer:

   {FIXED DATETRUNC('year', [Order Date]) : SUM([Sales])} -> Option A

5. Quick Check:

   FIXED + DATETRUNC('year') fixes yearly total for comparison [OK]

Hint: Use FIXED with DATETRUNC('year') for yearly totals [OK]

Common Mistakes:

• Using YEAR() instead of DATETRUNC for FIXED
• Using INCLUDE or EXCLUDE instead of FIXED
• Excluding month instead of fixing year