**StudySAS Blog: Mastering Clinical Data Management with SAS**

The SORT Procedure (Proc Sort): Options We can do many things using PROC SORT like create a new data set ,  subset the data ,  rename/ drop/ keep variables ,  format, or label your variables  etc Options Available with Proc Sort: OUT= OPTION DESCENDING OPTION DROP=, KEEP=, AND RENAME= OPTIONS  FORMAT AND LABEL STATEMENTS WHERE= OPTION OR WHERE STATEMENT FIRSTOBS= AND OBS= OPTIONS NODUPRECS AND NODUPKEY OPTIONS DUPOUT A common interview question for SAS jobs is "What is the difference between proc sort nodup and proc sort nodupkey?". The answer the interviewer is expecting is usually "proc sort nodup gets rid of duplicate records with the same sort key but proc sort nodupkey gets rid of other records with the same sort key". However, this is not correct. Read mo re at……. Common Programming Mistake with Proc Sort NODUPRECS - Equivalent of NODUPKEY in PROC SQL Ian Whitlock Explains... NODUPKEY is like FIRST. processing. Both d...

Removing Duplicate Observations in SAS: A Comprehensive Guide Removing Duplicate Observations in SAS: A Comprehensive Guide In data analysis, it's common to encounter datasets with duplicate records that need to be cleaned up. SAS offers several methods to remove these duplicates, each with its strengths and suitable scenarios. This article explores three primary methods for removing duplicate observations: using PROC SQL , the DATA STEP , and PROC SORT . We will provide detailed examples and discuss when to use each method. Understanding Duplicate Observations Before diving into the methods, let's clarify what we mean by duplicate observations. Duplicates can occur in different forms: Exact Duplicates: All variables across two or more observations have identical values. Key-Based Duplicates: Observations are considered duplicates based on the values of specific key variables (e.g., ID, Date). The ...