title: SAS Proc SQL to add a constant to a variable
body: <p>I have a SAS dataset with numeric variables <code>to</code>, <code>from</code>, and <code>weight</code>.  Some of the observations have value 0 for <code>weight</code>.  I need all the <code>weight</code> values to be positive, so I wish to simply add 1 to all <code>weight</code> values.</p>
  
  <p>How can I do that using Proc SQL?</p>
  
  <p>I have tried the following, but it doesn't work:</p>
  
  <pre><code>proc sql;
      update mylib.mydata
          set weight=weight+1;
  quit;
  </code></pre>
  
  <p>The error is:</p>
  
  <pre><code>ERROR: A CURRENT-OF-CURSOR operation cannot be initiated because
  the column "weight" cannot be used to uniquely identify a row
  because of its data type.
  </code></pre>
  
  <p>Also, <code>mylib</code> refers to a Greenplum appliance.  This might be the problem...</p>