A
null value indicates the absence of information. A null value means that a real value is unknown
or nonexistent. That is, no data is assigned to the
column in that specific row. A null value is not a zero or a blank.
A null value is represented by SAS Federation Server either as a SAS
missing value or an
ANSI SQL null value:
SAS missing value
The SAS missing value indicators ( . , ._, .A-.Z, and ' ') are known values that indicate
nonexistent data.
A SAS missing value is interpreted as its internal floating-point representation.
By default, SAS prints a missing numeric value as a single period (.) and a missing
character value as a blank space. A
SAS data set represents null values with SAS missing values.
ANSISQLnull value
Table data with an ANSI null value has no real data value; it is metadata that indicates
an unknown value. Third-party
relational databases represent null values with ANSI SQL null values.