title: Must declare Scalar variable - error from parameter
body: <p>I have a dataset query as below:</p>
  
  <pre><code>SELECT col1, col2
  FROM Table
  WHERE @DatabaseGrowth = 'DatabaseGrowthByLast7Days'
  
  UNION ALL
  
  SELECT col3, col4
  FROM Table
  WHERE @DatabaseGrowth = 'DatabaseGrowthByLast4Weeks'
  </code></pre>
  
  <p>and have a parameter named <code>DatabaseGrowth</code>. While running the report, if I select <code>DatabaseGrowthByLast7Days</code>, it should return <code>7Days</code>. But, it is showing error </p>
  
  <blockquote>
    <p>Must declare Scalar variable "@DatabaseGrowth"</p>
  </blockquote>
  
  <p>What is wrong with my dataset code?
  The above code is sample code of my actual code.</p>
  
  <p>Edited the code above.</p>