Importance of Warnings and Notes messages from SAS log
The errors I will list here will be very few in number. They are errors that you will likely make at some time if you do not remain alert. These errors could have serious consequences so that is why I have described them as "deadly errors". Missing "by" statement in merge: Using "set" instead of "merge": Existing "in" variable in merge: "Flag" variables in data steps: "Fixing" data during a merge: Averaging averages: Merging in Key Variables: Read more at........... Importance of Warnings and Notes messages from SAS log A Utility Program for Checking SAS Log Files