title: Using CASE within a single query to update multiple columns in SQL table
body: <p>I wanted to write an update query to update multiple columns in a SQL table as <code>BLANKS</code> wherever their current value is <code>NULL</code>. </p>
  
  <p>I wrote a query like the one below but it does not seem to have updated correctly all the appropriate rows where some / all of these column(s) are having <code>NULL</code>. </p>
  
  <pre><code>Update A SET     
  A.Col1 = CASE WHEN A.COl1 is NULL THEN ' ' END,     
  A.Col2 = CASE WHEN A.COl2 is NULL THEN ' ' END,    
  A.Col3 = CASE WHEN A.COl3 is NULL THEN ' ' END,    
  A.Col4 = CASE WHEN A.COl4 is NULL THEN ' ' END    
  FROM Table1 A 
  </code></pre>
  
  <p>Is there anything wrong with the query above? Can we not use <code>CASE</code> in the way how I have used above?</p>