title: Adding hash column to table
body: <p>I'm trying to hash the columns of some tables using SHA256 and store the hashed value. I'm thinking of using <code>HASHBYTES</code> to achieve this but the function can only take one string argument as the hash input - <code>HASHBYTES('SHA2_256', COLUMN_1)</code>. Is it possible to hash multiple columns (including ones that are not strings)?</p>
  
  <p>The reason I want to do this is so I can identify rows that have been changed or added using the hash value to later use in an ETL process. One of the tables I want to hash contains these columns:</p>
  
  <pre><code>[CompanyCode] [varchar](4) NULL,
  [CompanyNumber] [int] NULL,
  [CompanyDescription] [varchar](20) NULL,
  [CompanyAddress] [varchar](60) NULL,
  [EffectiveDate] [date] NULL
  </code></pre>
  
  <p><strong>Note that I cannot add a timestamp with a trigger since the table is managed by a third party.</strong></p>