Using IF versus WHERE for conditionals

[pgonatas12]

For the SaS Practice Exam for the  A00-231 exam, one of the questions involves only taking values of a group equal to A or B. When I use WHERE group in ('A','B');, it gives me 4897 rows. The correct answer, which uses IF group in ('A','B'), gives 4992 rows. I'm not sure why there is a discrepancy here, I figures they should do the same thing.

[ballardw · Accepted solution]

Where would apply  to the values as read from data on the SET statement.

IF any of the values of the variable are changed, such as changing a lower case 'a' to 'A' the Where would have been applied before the change. An IF statement appearing after a change to the variable would use the new value of the variable for selection.