この関数は Google スプレッドシートでも Excel と同じように機能します。構文も引数も同じです。
NA()The NA function is used to mark cells as intentionally empty or missing data by returning the #N/A error value. This helps prevent calculations from including incomplete data, as any formula referencing a cell with #N/A will also return #N/A.
=NA()結果: #N/A
Returns the #N/A error value.
=IF(A1="", NA(), A1*10)結果: #N/A (if A1 is empty)
Returns #N/A if cell A1 is empty, otherwise multiplies A1 by 10.
It is useful for signaling that data is missing, which prevents other formulas from performing calculations on incomplete information.