title: With SQL 2008 spatial functions, how can I construct a LINESTRING representing the line between two (or more) POINT instances?
body: <p>Define a couple of points as follows:</p>
  
  <pre><code>declare @p1 geography, @p2 geography
  set @p1 = 'POINT(1 2)'
  set @p2 = 'POINT(6 8)'
  </code></pre>
  
  <p>Now I'd like to obtain the shortest line between these two points. What function can I use to get this line? (i.e., it should output a LINESTRING(1 2, 6 8) or LINESTRING(6 8, 1 2))</p>
  
  <p>I know I could do this by formatting the points as WKT, doing a bit of string manipulation, and then parsing it back, but that seems ridiculous. Surely there's some way to construct a linestring directly from a series of points?</p>
  
  <p>(With "geometry" types, I can use @p2.STUnion(@p1).STConvexHull(), but there's no STConvexHull() for a geography type.)</p>