I would like to apply natural number sort order to the attribute representing members' age, but including sub zero values and empty values in addition to the natural human age. I would like to know whether label column accepts such sub zero values or empty values inevitably flown into from the manually input source data like logs.
Yes! You have to change the data type of the label from Varchar(128) to Integer.
There are two ways to do it:
This data type accepts also sub zero values. For "null" or "empty" values there has to be upper case null string "NULL" in the source data.