Common LOD use cases (customer first purchase, cohorts) in Tableau - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to calculate the first purchase date per customer using LOD expression.

Tableau

{ FIXED [Customer ID] : MIN([1])}

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A[Purchase Date]

B[Order Date]

C[Transaction Date]

D[Sale Date]

Attempts:

3 left

💡 Hint

Common Mistakes

Using a date field that is not related to purchase, like shipping date.

The LOD expression fixes the calculation at the customer level and finds the earliest order date, which represents the first purchase date.

2fill in blank

medium

Complete the LOD expression to count unique customers who made their first purchase in each cohort month.

Tableau

COUNTD({ FIXED DATETRUNC('month', [Order Date]) : IF DATETRUNC('month', [Order Date]) = [1] THEN [Customer ID] END })

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ADATETRUNC('month', [First Purchase Date])

BDATETRUNC('month', [Order Date])

CDATETRUNC('year', [Order Date])

DDATETRUNC('day', [Order Date])

Attempts:

3 left

💡 Hint

Common Mistakes

Using order date instead of first purchase date for cohort grouping.

This expression compares the order month to the customer's first purchase month to identify cohort members.

3fill in blank

hard

Fix the error in the LOD expression to calculate the number of months since a customer's first purchase.

Tableau

DATEDIFF('month', [1], [Order Date])

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A[First Purchase Date]

B[Customer First Purchase]

CMIN([Order Date])

D{ FIXED [Customer ID] : MIN([Order Date]) }

Attempts:

3 left

💡 Hint

Common Mistakes

Using a field that is not aggregated or calculated per customer.

The first purchase date must be calculated using a FIXED LOD expression to get the minimum order date per customer.

4fill in blank

hard

Fill both blanks to create a cohort calculation that assigns customers to their first purchase month and calculates retention month.

Tableau

DATETRUNC('month', [1]) AS CohortMonth, DATEDIFF('month', [2], [Order Date]) AS RetentionMonth

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A[Order Date]

B{ FIXED [Customer ID] : MIN([Order Date]) }

C[First Purchase Date]

D[Customer ID]

Attempts:

3 left

💡 Hint

Common Mistakes

Using order date directly instead of first purchase date for cohort assignment.

Both blanks use the FIXED LOD expression to get the customer's first purchase date for cohort and retention calculations.

5fill in blank

hard

Fill all three blanks to write a cohort retention calculation: assign cohort month, calculate retention month, and count distinct customers.

Tableau

{ FIXED DATETRUNC('month', [1]), DATEDIFF('month', [2], [Order Date]) : COUNTD([3]) }

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A[Order Date]

B{ FIXED [Customer ID] : MIN([Order Date]) }

C[Customer ID]

D[First Purchase Date]

Attempts:

3 left

💡 Hint

Common Mistakes

Counting orders instead of customers, or using order date instead of first purchase date.

The cohort month and retention month use the fixed first purchase date, and the count distinct is on Customer ID to count unique customers.