Hi SAS Community,   Let's say I have one SAS dataset with one variable called ID1 with 4 values (1-4) and another variable called ID2 with 4 values (1-3 and then one missing value).   ID1   ID2 1       1 2      2 3      3 4      I want to fill in the missing value of ID2 with the value in ID1. In data set programming I would usually say IF ID2 = '    ' then ID2 = ID1.  This will give me the value of 4 for the ID2 missing record.  This is easy in the SAS Datastep, but does anyone know how to accomplish the same result using PROC SQL?  Please note, I will have to do this over many records and we will be using SQL more often, but at this point if I can have the PROC SQL code that would help me greatly.    I tried using CASE WHEN but it doesn't seem to look across more than one variable.  Thanks   ... View more