>>What would be the difference in using DO WHILE vs SCAN WHILE...?
>>Is there a performance issue?
>>
>>Thanks in advance, M.
>My preference is for SCAN. In addition to what has been said, I think it is slightly cleaner especially if you have both a WHILE and FOR clause.
>
>One thing to be aware of, however. Nested SCANs do not work as expected because of the extra SKIP at the second ENDSCAN.


Here is workaround shown on Dragan's code .

scan 
   <...some code>
      
      scan while &WhileCondition
         <more code>

           scan while &InnerWhileCondition
              <more code>
           endscan   
           skip -1   && Workaround to 'rewind' table one skip back

      endscan   
      skip -1        && will do the trick

endscan   

Nested scans will work properly like this.

Also, additional FOR clauses in inner scans might 'mess up'
smooth, top to bottom flow in above scenario

Rgds++