title: R Markdown SAS code chunks with proc sql not performing as expected
body: <p>I'm using R Markdown to create a SAS proc sql tutorial but I have found several instances where code chunks with proc sql are not working as expected. </p>
  
  <p>First, the outobs=N and inobs=N options will not evaluate and result in this error:</p>
  
  <pre><code>Error in engine(options) : Calls: &lt;Anonymous&gt; ... process_group.block -&gt; call_block -&gt; block_exec -&gt; in_dir -&gt; engine
  In addition: Warning message: In system2(cmd, code, stdout=TRUE, stderr= TRUE, eng = options$engine.env): running command '"C:/Program Files/SASHome/SASFoundation/9.4/sas.exe" sas3afc64d1332b.sas -nosplash -ls 75' had status 1
  </code></pre>
  
  <p>Next, matching is not appearing to work in the proc sql code chunks. I have tried a subquery and a full join without success in R Markdown, while the same code works in base SAS.</p>
  
  <p>Reproducible code:</p>
  
  <pre><code>require(knitr)
  require(SASmarkdown)
  saspath &lt;- "C:/Program Files/SASHome/SASFoundation/9.4/sas.exe"
  sasopts &lt;- "-nosplash -ls 75"
  
  </code></pre>
  
  <pre><code>/*filter with a subquery*/
  data roster;
      input Person $;
      datalines;
      Tiffany 
      Tiffany 
      Barbara
      Henry 
      Carol
      Jane 
      Tiffany 
      Ronald 
      Thomas
      William
      William
      Henry 
      Carol
      Carol
      Ronald 
      Thomas
  ;
  
  proc sql;
  title "Subquery";
      select *
      from sashelp.class
      where Name in 
          (select distinct Person
          from roster);
  quit;
  
  proc sql;
  title "Full join";
       select *
       from sashelp.class a full join roster b
       on a.Name = b.Person;
  quit;
  
  </code></pre>
  
  <p>For the subquery above, the log results in R Markdown say that no rows were selected. The results from the full join are: </p>
  
  <pre><code>##            Name      Sex       Age    Height    Weight  Person
  ##            -----------------------------------------------------
  ##                                  .         .         .   Barbara
  ##                                  .         .         .   Carol  
  ##                                  .         .         .   Carol  
  ##                                  .         .         .   Carol  
  ##                                  .         .         .   Henry  
  ##                                  .         .         .   Henry  
  ##                                  .         .         .   Jane   
  ##                                  .         .         .   Ronald 
  ##                                  .         .         .   Ronald 
  ##                                  .         .         .   Thomas 
  ##                                  .         .         .   Thomas 
  ##                                  .         .         .   Tiffany
  ##                                  .         .         .   Tiffany
  ##                                  .         .         .   Tiffany
  ##                                  .         .         .   William
  ##                                  .         .         .   William
  ##            Alfred    M          14        69     112.5          
  ##            Alice     F          13      56.5        84          
  ##            Barbara   F          13      65.3        98          
  ##            Carol     F          14      62.8     102.5          
  ##            Henry     M          14      63.5     102.5          
  ##            James     M          12      57.3        83          
  ##            Jane      F          12      59.8      84.5          
  ##            Janet     F          15      62.5     112.5          
  ##            Jeffrey   M          13      62.5        84          
  ##            John      M          12        59      99.5          
  ##            Joyce     F          11      51.3      50.5          
  ##            Judy      F          14      64.3        90          
  ##            Louise    F          12      56.3        77          
  ##            Mary      F          15      66.5       112          
  ##            Philip    M          16        72       150          
  ##            Robert    M          12      64.8       128          
  ##            Ronald    M          15        67       133          
  ##            Thomas    M          11      57.5        85          
  ##            William   M          15      66.5       112
  </code></pre>
  
  <p>So it looks like proc sql is just not matching the Name/Person columns? I've tried the strip() function to be sure spaces are not the issue. </p>
  
  <p>Again, if I run these code snippets in SAS, the subquery and join work without issue. Thanks in advance for any insight into why this code is not working as expected!</p>