title: Sum time in SQL Stored procedure
body: <p>How sum time in SQL my procedure return:</p>
  
  <pre><code>START   --    FINISH   ---   TOTAL
  18:14:47    20:32:54    02:18:06
  12:35:45    15:06:06    02:30:21
  18:08:26    21:25:39    03:17:12
  </code></pre>
  
  <p>I need sum column TOTAL (08:05:40)</p>
  
  <p>My stored procedure:</p>
  
  <pre><code>Alter PROCEDURE [dbo].[timeTotal] 
  @userName nvarchar(50)
  AS
  BEGIN
  
      SELECT
  
              CONVERT(VARCHAR(8),dateadd(HH,7,workStart),108) AS workStart,
              CONVERT(VARCHAR(8),dateadd(HH,7,workFinish),108) AS workFinish,
              CONVERT(VARCHAR(8),workFinish - workStart,108) AS total
  
  
      FROM workTime
      WHERE userName = userName
  
  
  END
  </code></pre>
  
  <p>I need get 08:05:40</p>