QUERY: create operator ##+ (leftarg=int4, rightarg=int4, procedure = int4pl);
QUERY: create operator ##+ (rightarg=int4, procedure=int4fac);
QUERY: create operator ##+ (leftarg=int4, procedure=int4inc);
QUERY: select 4 ##+ 4;
?column?  
--------- 
8         
QUERY: select ##+ 4;
?column?  
--------- 
24        
QUERY: select (4 ##+);
?column?  
--------- 
5         
QUERY: drop operator ##+(int4,int4);
QUERY: drop operator ##+(none, int4);
QUERY: drop operator ##+(int4, none);
