Create the Boolean Flag.
But when you filter the dashboard to "2024" only, that MIN changes. The customer who first bought in 2020 suddenly shows a first purchase date of 2024. The calculation is . fixed calculation tableau
This is wrong. You need a calculation that ignores the date filter. The FIXED calculation tells Tableau: "Compute this value using these specific dimensions, and ignore all other filters (except context filters and data source filters)." The Syntax FIXED [Customer Name] : MIN([Order Date]) Translation: "Lock onto each unique Customer. Look at all the Order Dates available for that customer (ignoring my current date filters). Give me the very first one." Real-World Example: Customer Retention Imagine you want to know how many new customers you acquired each month. Create the Boolean Flag