Thoroughly updated for SAS 9, this second edition addresses tasks that nearly every SAS programmer needs to do - that is, make sure that data errors are located and corrected. Written in Ron Cody's signature informal, tutorial style, this book develops and demonstrates data cleaning programs and macros that you can use as written or modify for your own special data cleaning needs. Each topic is developed through specific examples, and every program and macro is explained in detail. You'll learn how to find and correct errors in character and numeric values develop programming techniques related to dates and missing values use SQL approaches to data cleaning develop techniques for correcting your data errors use integrity constraints and audit trails to prevent errors from being added to a clean data set Novice and experienced SAS users will discover ways to detect and correct data errors while learning how to apply DATA step programming techniques and SAS procedures.