Salesforce Updated Analytics-DA-201 Exam Questions and Answers by mitchell

Both IFNULL and ZN can replace null numeric values with zero. IFNULL([Profits], 0) returns the Profit value when it is non-null and explicitly returns 0 when the field is null. ZN([Profits] ) is a specialized null-handling function that returns the original expression when a value exists and zero when it is null. Tableau’s documentation specifically describes ZN as useful for replacing null numeric values with zeros. ISNULL([Profits]) returns a Boolean TRUE/FALSE result rather than a numeric replacement. Option C is also inappropriate because nulls cannot be reliably tested by ordinary equality or inequality comparisons; Tableau supplies ISNULL for that purpose, and the proposed formula does not substitute zero. Therefore, A and D both produce the required numeric result while retaining existing non-null Profit values.

The formula in option B calculates the percent difference in sales relative to the same quarter the previous year. It subtracts the sales of the same quarter from the previous year from the current year’s sales, and then divides this by the previous year’s sales. This gives a percentage change, which aligns with what is shown in the Calculation field of your dataset. The LOOKUP function returns the value of a specified offset from the current row in the partition. In this case, the offset is -4, which means the value of the same measure four rows above the current row. This corresponds to the same quarter of the previous year, assuming the data is sorted by quarter. References:

LOOKUP Function - Tableau

Table Calculations - Tableau

Tableau Certified Data Analyst Study Guide

https://help.tableau.com/current/pro/desktop/en-us/parameters_swap.htm

This formula uses a parameter (Pick Measure) to switch between the Sales and Profit measures. When the user selects ' 1 ' , it shows Sales, and when ' 2 ' is selected, it shows Profit. This dynamic switching is enabled by the Case function.