title: Group by using LIKE Operator and ignore NULL value
body: <p>I have written one query to group the tax items, if tax is null, i dont want to display the tax name. How to do this? Please check my sql server statement:</p>
  
  <pre><code> SELECT     
     'CENTRAL EXCISE DUTY'    AS 'TaxName',
     SUM(TaxAmount)       AS 'Tax'
   FROM
     PMT_InvoiceTaxAttribute
   WHERE 
     InvoiceID = 100 
     AND TaxAttributeName NOT LIKE '%IBR%' 
     AND TaxAttributeName NOT LIKE '%CST%' 
     AND TaxAttributeName NOT LIKE '%VAT%'
   UNION
   SELECT
     'CST'            AS 'TaxName',
     SUM(TaxAmount)       AS 'Tax'
   FROM
     PMT_InvoiceTaxAttribute
   WHERE 
     InvoiceID = 100   
     AND TaxAttributeName LIKE '%CST%'
   UNION
   SELECT
     'VAT'            AS 'TaxName',
     SUM(TaxAmount)       AS 'Tax'
   FROM
     PMT_InvoiceTaxAttribute
   WHERE 
     InvoiceID = 100   
     AND TaxAttributeName LIKE '%VAT%'
  </code></pre>
  
  <p>This Query gives the Output as follows:</p>
  
  <pre><code>      TaxName                     Tax
     -------------              -----------
    CENTRAL EXCISE DUTY             15000
          CST                       NULL
          VAT                       NULL
  </code></pre>
  
  <p>Here, I don't want to display the CST and VAT since it has null value.</p>