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Revision: 5753
at April 1, 2008 13:39 by webonomic
Initial Code 
/*Most of us SAS programmers approach SQL as simply a data extraction and table joining tool. Since most of us have used the data step longer than SQL, we tend to leave the logic programming to the data step with its if/then statements. However, SQL does have a way of assigning values conditionally. With the CASE expression you can test and assign values logically.
The basic syntax is:

CASE value  
   WHEN condition THEN result  
   WHEN condition THEN result  
   ELSE result
END

In the code below I am just assigning a 1 or a 0 to a column/variable named bool_tf.
Using the CASE expression is pretty straightforward and is another great way to use SQL to get more coding done in fewer steps.
*/

data myData;
  input answer $;
datalines;
true
false
true
true
false
false
true
;
proc sql;
  create table a as
  select answer, 
         case substr(answer,1,1)
              when 't' then 1
       when 'f' then 0
  end as bool_tf
  from myData;
quit;
Initial URL 
http://datasteps.blogspot.com/2007/11/using-logical-expressions-in-sql.html
Initial Description 

                                

                                                            

                                    

                                        

                                        Initial Title
                                        

                                    

                                    
Logical Expressions In SQL

                                

                                                            

                                    

                                        

                                        Initial Tags
                                        

                                    

                                    
sql

                                

                                                            

                                    

                                        

                                        Initial Language
                                        

                                    

                                    
SAS