Before you can interleave data sets,
the data must be sorted by the same variable or variables that will
be used with the BY statement that accompanies your SET statement.
For example, the Research
and Development division and the Publications division of a company
both maintain data sets containing information about each project
currently under way. Each data set includes these variables:
specifies a unique
code that identifies the project.
specifies the name
of a department that is involved in the project.
specifies the last
name of the manager from Department.
specifies the number
of people working for Manager on this project.