I have a table of OSM geographic roads in MSSQL 2012.
I want to create a new column with the centroid of each road (So I can set center on OpenLayers map for each road).
How can I do it ?
I think what you want to do is this - to get the closest point on the road to the centre of the road's bounding box? If so, then this will do the trick:
The ShortestLineTo method is new in MSSQL 2012, and there's some discussion of using it in this way here.