I haven't used that pariticular keyword syntax in a SQL statement, in or out of ALM. But I did find these two references that you may find helpful, since you say you are new to SQL.
http://stackoverflow.com/questions/14189216/case-in-select-statement
http://msdn.microsoft.com/en-us/library/ms181765.aspx
http://stackoverflow.com/questions/14189216/case-in-select-statement
http://msdn.microsoft.com/en-us/library/ms181765.aspx