coordinate system - Reprojecting all geometries in PostGIS table?

I created a spatial table with SRID:4326. Now I want to change total projection to SRID:32644 into a new table. The old table should remain unchanged.

Answer

If you're on PostGIS 2.0+, you can go:

ALTER TABLE mytable 
  ALTER COLUMN geom 
  TYPE Geometry(Point, 32644) 
  USING ST_Transform(geom, 32644);