good

Merge branch 'master' of https://github.com/merlintang/sgb

README.md

@@ -10,4 +10,47 @@ http://www.postgresql.org/docs/9.2/static/install-procedure.html
 
 ## Sample Sql queries
 
+```sql
+
+//create table
+CREATE TABLE tmp (
+    id         integer,
+    col1       double,
+    col2       double
+);
+
+//insert data 
+insert into tmp values (1, 2.0,3.0)
+insert into tmp values (2, 3.0,4.0)
+
+//execute query
+//SGB-All
+         select  avg(col1) as centerx, avg(col2) as centery
+   			 min(col1) as p1x, min(col2) as p1y
+   			 max(col1) as p2x, max(col2) as p2y from tmp
+   			 group by col1, col2 distanceall within 2
+   			 on_overlap any 
+   			 metric lone;
+
+   			  select  avg(col1) as centerx, avg(col2) as centery
+   			 min(col1) as p1x, min(col2) as p1y
+   			 max(col1) as p2x, max(col2) as p2y from tmp
+   			 group by col1, col2 distanceall within 2
+   			 on_overlap eliminate 
+   			 metric lone;
+
+   			  select  avg(col1) as centerx, avg(col2) as centery
+   			 min(col1) as p1x, min(col2) as p1y
+   			 max(col1) as p2x, max(col2) as p2y from tmp
+   			 group by col1, col2 distanceall within 2
+   			 on_overlap new_group 
+   			 metric lone;
+
+
+//SGB-Any	 
+   			 select  avg(col1) as centerx, avg(col2) as centery
+   			 min(col1) as p1x, min(col2) as p1y
+   			 max(col1) as p2x, max(col2) as p2y from table
+   			 group by col1, col2 distanceany within 2
+   		   metric lone;