Automatic Handling of N/A Values

N/A values are handled automatically in selection and value expressions and tabulations.

N/A Values in Selection and Value Expressions

Assuming that missing values are represented by our special N/A values, what happens when these values are used in a computation? Specifically, if we create a computed column that references one or more other columns, and those columns contain N/As, what will be the value of the computed column? 

For example, if col3 is col1+col2 and one or both of col1 and col2 are N/A, what will col3 be? What if col3 is col1>col2 or round(col1;10)

For most functions and operators, if any argument is N/A, the result is N/A, but this is not always true. See the description of each operator and function for details about N/A handling.

N/A Values in Tabulations

What happens when N/A values are encountered in a quick summary or tabulation? 

For example, when summing the values in a particular group of rows, what if some of the values are N/A? 

The answer is that, as a general rule of thumb, N/A values are ignored. In the case of sum, for example, the result is the sum of the non-N/A values. But there are exceptions to the rule. See the description of each summary type for details about N/A handling in quick summaries, tabulations, and cross tabulations.