Advanced Topics

Deciding How to Specify Selection Criteria

Use the following guidelines to determine when to use a SAS WHERE clause and when to use a view WHERE clause.

Include a WHERE clause in your view descriptor when you want to do the following:

restrict users of view descriptors to certain subsets of data
prevent users from sequentially passing all the ADABAS data
use syntax not available in the SAS WHERE clause, such as periodic group occurrence syntax or multiple-value compares.

Use a SAS WHERE clause when the previous guidelines do not apply and you want to meet the following criteria

have more run-time flexibility in subsetting data
use SAS WHERE clause capabilities that the view WHERE clause does not support, such as arithmetic expressions, truncated comparisons, or pattern matching
use conditions on fabricated data fields such as ISN, periodic group _OCCUR variables, or any individually selected multiple-value fields
combine AND and OR conditions using non-descriptor data fields.