I have a PostGIS table in a projected coordinate system (EPSG: 28355 or MGA94 Zone 55). In QGIS (with the PostGIS manager plugin) I calculate a coordinate by performing the following SQL:
UPDATE gisprod.buildings SET easting = x(centroid(the_geom))
Now I want to add a "lat" and "lon" field to this table and calculate the values using the appropriate coordinate system, in this case that would be (EPSG:4283 or GDA94).
Is there a way I can specify in the SQL statement to calculate the x/y coord using a different coordinate system?