12/12/2023 0 Comments Tableau prep alternativesFor example, to translate the letter grades into numerical grades, as shown above, the CASE formula in Figure 7 will also work!įigure 7: The ELSE clause is optional. For many calculations, both CASE and IF statements can be used to get the same result. Comparing to CASE Statementsįor the purpose of comparing CASE statements to the IF statements, I will use the IF THEN type of IF statement. Many times though, you’re better off using the usual IF THEN statement just make sure that your formula is correctly handling unknown results. So, when it comes to IF statements in Tableau, use the IIF statement when the calculation is simple or if you’re not sure about the data quality of the field you’re testing. The IIF formula in Figure 6 is much more difficult to write and understand.įigure 5: Using IF THEN ELSEIF… is usually the best method for nesting these kinds of functions.įigure 6: While this formula is valid, it is a really bad method for performing this calculation! The IF THEN formula is fairly straightforward and easy to understand (Figure 5). For example, let’s say that I want to translate all the A-F grades into a numerical grade in order to compute their GPAs. IF THEN statements, however, are far better than IIF statements when function nesting is necessary. There is an easy workaround to this problem with the IF THEN statement using an ISNULL function, but it’s messier (see Figure 4).įigure 4: IIF THEN statements can properly account for UNKNOWN results by using functions like the ISNULL shown in this formula. In this way, the IIF statement is superior to the IF THEN statement. Figure 3 shows this in a crosstab with the differences highlighted.įigure 3: When IF THEN statements do not account for unknown results, they can misrepresent the data as shown in this example.Īs you can see, the IIF calculation reports the data more accurately and points out when there are nulls. The IF THEN formula would assign those rows with missing grades a “Do Nothing” value, but the IIF formula would leave them null. In our example, let’s say that the math teacher forgot to enter some grades. In this case, the IF THEN unknown results are treated and given the same value as the false results whereas the IIF statement returns “null” or another specified value for unknown results. This typically happens when there are null values in the data set. The primary difference between these two statements can be seen when the data contains values that yield an “unknown” result from the boolean comparison. However, it might not be as readable if the user is not familiar with it. If so, the IIF statement is simpler and less prone to making errors. When an UNKNOWN value is not specified, the formula will return null for that row.ĭepending on the data, syntax might be the only difference between these two. I could use a simple IF THEN statement (Figure 1) or an IIF statement (Figure 2).įigure 1: This formula separates the boolean results into two categories: TRUE and everything else (FALSE and Unknown).įigure 2 This formula separates the boolean results into three categories: TRUE, FALSE, and UNKNOWN. And, I want a calculated field to identify these instances. Let’s say that for every “A” grade earned, a certificate needs to be issued. To illustrate these and other differences throughout this article, I’ll use a simple data set of student grades. There is also the IIF statement, which handles unknown results differently and uses a different syntax. There is the classic IF THEN statement with the ability to add multiple ELSEIF components. The Different Types of IF Statementsīefore discussing CASE statements, it is important to point out the different types of IF statements in Tableau. What are the differences between CASE and IF statements when making calculated fields in Tableau? How do different types of IF statements vary? When is it better to use one of these statements over the others? That is what I’ll address in this article.
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