No.

In SAS the default missing value for a NUM variable is a dot   .    .

Also .a, .b  ....., .z are missing values you can assign it to a NUM variable for missing coding.

Note .<.a<.b<......<.z

HTH

缺失值
数值的为一个 点号
字符型为一个空格
你可以再DATA步里面用MISSING命令来制定替代缺失值的标示符

Thanks you very much!

for numerical data, missing value is a period;character data is a blank.