I'm currently learning to use PostgreSQL and PostGIS. I would like to know how to write the SQL that would allow me to select 200 random points within a radius of 500m from a user defined centre point. Currently I have the database containing all my records, with an individual row for ID, latitude and longitude. The co-ords are in WGS84. The 'points' refer to shops.
Once I have the 200 randomly selected points, I would then like to edit a further two coloumns ("Status" and "Time") to show the selected points are closed and the time which they closed.
What would you suggest is the simplest way to perform this?