coordinate_transform.sql

-- You update the SRID for your table first. Then you reverse that update within a SQL query so you can transform the actual coordinates to their new EPSG. 
-- Otherwise you'll have Lat/Long coordinates for a metric projection or vice-versa.

SELECT Updategeometry_columnetrySRID('table','geometry_column',new_EPSG);
ALTER TABLE table
    ALTER COLUMN geometry_column TYPE geometry(geometry_type,new_EPSG) USING ST_Transform(ST_SetSRID(geometry_column,old_EPSG),new_EPSG);
SELECT ST_AsText(geometry_column) FROM table;