Advanced SQL with SAS

Chapter 2: Missing Values

Data queries and analyses usually require the presence of entries such as numbers or strings in a table. Missing values indicate the absence of values. While entries represent the presence of information, missing values indicate absence of information. In data analysis, missing values are more of the rule than the exception. (See Schendera, 2020/2007, Chapter 6.)

A data set can be described as complete or incomplete by the extent to which the occurrence of missing values is observed. Complete data is observed when there is nothing missing within the data set, variable, or row. Incomplete data is observed when there are missing occurrences within the data set, variable, or row. If a data set, variable, or row contains ...