Common LOD use cases (customer first purchase, cohorts) in Tableau - Cell-by-Cell Formula Trace

Sample Data

Sales data showing customer purchases with dates and sales amounts.

Cell	Value
A1	CustomerID
B1	OrderDate
C1	Sales
A2	C001
B2	2023-01-10
C2	100
A3	C002
B3	2023-01-15
C3	150
A4	C001
B4	2023-02-05
C4	200
A5	C003
B5	2023-02-20
C5	300
A6	C002
B6	2023-03-01
C6	120

Formula Trace

{ FIXED [CustomerID] : MIN([OrderDate]) }

Step 1: Identify all orders for CustomerID 'C001'

Step 2: Find the earliest order date for C001

Step 3: Repeat for CustomerID 'C002'

Step 4: Find earliest order date for C002

Step 5: Repeat for CustomerID 'C003'

Step 6: Earliest order date for C003 is

Step 7: Result: For each customer, their first purchase date is

Cell Reference Map

    A         B           C
1 CustomerID OrderDate   Sales
2 >C001     >2023-01-10  100
3 >C002     >2023-01-15  150
4 >C001     >2023-02-05  200
5 >C003     >2023-02-20  300
6 >C002     >2023-03-01  120

Arrows show the CustomerID and OrderDate columns used in the LOD calculation.

The formula uses CustomerID and OrderDate columns to find the earliest purchase date per customer.

Result

    A         B           C           D
1 CustomerID OrderDate   Sales     First Purchase
2 C001       2023-01-10  100       2023-01-10
3 C002       2023-01-15  150       2023-01-15
4 C001       2023-02-05  200       2023-01-10
5 C003       2023-02-20  300       2023-02-20
6 C002       2023-03-01  120       2023-01-15

The new column 'First Purchase' shows each customer's earliest order date repeated for all their orders.

Sheet Trace Quiz - 3 Questions

What does the FIXED LOD expression { FIXED [CustomerID] : MIN([OrderDate]) } calculate?

A The earliest order date for each customer

B The total sales per customer

C The latest order date for each customer

D The average sales per order

Key Result

FIXED LOD expressions calculate an aggregate value fixed at the level of specified dimension(s), ignoring filters or row context.