Hi

 

I have an expression such as -

 

select ST_distance(st_centroid(p_id.p_id.the_geom), st_boundary(p_id.p_id.the_geom))/2 + 15000
   from p_id.p_id
   where p_id.p_id.process_id = '1012' ;

 

This works

 

I can access the number 15000 from a table as a variable. 

 

I want to be able to also access the + (or -) from a table as a variable but can't figure out how to do this.

 

Is it possible to store math operators and access them from a table??

 

Bob