title: how to use IF and ELSE statements with both text and numerical columns
body: <pre><code>SELECT     DATASET, BLOCKID, CATEGORY, ROUND(TONNES, 0) AS TONS, ROUND(VOLUME, 0) AS VOLUME, ROUND(EU3O8, 0) AS GRADE, ROUND(TONNES * EU3O8 / 1000, 0) 
                        AS Metal_kg
  FROM         dbo.tblPTEvaluationRep_GC75ppm
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/FuzTR.jpg" alt="Picture"></p>
  
  <p>I can do basic calculations, I however now need to use what I think are "IF and ELSE" statements, but am unable to. </p>
  
  <p>The last column, Metal_kg should be IF CATEGORY = 'WST'or 'SEM' THEN '0' ELSE TONNES*EU3O/1000</p>
  
  <p>There are more categories than those listed in picture.</p>
  
  <p>I am unable to get any answer or it is unable to calculate my equation.</p>