SheetCompareNull value
The absence of a value in a cell or field. How a tool represents 'nothing', empty string, NULL, or zero, changes how it sorts, compares, and aggregates.
A null is the explicit absence of data, distinct from zero (a real number) and from an empty string (a string of length zero). Databases have a dedicated NULL; CSV has no way to express it, so a missing value is just an empty field, which is why CSV-to-JSON conversions have to decide whether an empty cell becomes "" or null.
Nulls cause subtle bugs in comparison and aggregation. Many systems treat NULL as 'not equal to anything', including another NULL, so two empty cells may or may not be reported as matching depending on the tool. Aggregations like averages often skip nulls, so the same data can yield different totals depending on whether blanks are nulls or zeros. Deciding how blanks are handled is essential before comparing or summing.