title: In T-SQL under MS SQL Server 2008, what does '@' mean in front of a parameter *value* that's a string literal?
body: <p>I have come across the following example code:</p>
  
  <pre><code>EXECUTE msdb.dbo.sysmail_add_profileaccount_sp        
                              @profile_name = @'SQL mail profile',        
                              @account_name = @'account name',        
                              @sequence_number = 1 ;     
  </code></pre>
  
  <p>What does '@' mean in front of the string literal, as in the example above:</p>
  
  <pre><code>@account_name=@'account name'
  </code></pre>
  
  <p>I understand that my question may stand true for any executable module's parameters in T-SQL, or maybe for any string literal in T-SQL in general, so the above is just a concrete example of what I'm looking at.</p>