Create aggregates only if they do not exist

src/pg/sql/04_py_agg.sql

@@ -10,10 +10,22 @@ CREATE OR REPLACE FUNCTION
     END
     $$ LANGUAGE plpgsql;
 
-
+-- Create aggregate if it did not exist
+DO $$
+BEGIN
+    IF NOT EXISTS (
+        SELECT *
+        FROM pg_catalog.pg_proc p
+            LEFT JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace
+        WHERE n.nspname = 'cdb_crankshaft'
+            AND p.proname = 'cdb_pyagg'
+            AND p.proisagg)
+    THEN
         CREATE AGGREGATE CDB_PyAgg(NUMERIC[]) (
             SFUNC = CDB_PyAggS,
             STYPE = Numeric[],
             INITCOND = "{}"
         );
-
+    END IF;
+END
+$$ LANGUAGE plpgsql;

src/pg/sql/11_kmeans.sql

@@ -41,9 +41,23 @@ BEGIN
 END
 $$ LANGUAGE plpgsql;
 
+-- Create aggregate if it did not exist
+DO $$
+BEGIN
+    IF NOT EXISTS (
+        SELECT *
+        FROM pg_catalog.pg_proc p
+            LEFT JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace
+        WHERE n.nspname = 'cdb_crankshaft'
+            AND p.proname = 'cdb_weightedmean'
+            AND p.proisagg)
+    THEN
         CREATE AGGREGATE CDB_WeightedMean(geometry(Point, 4326), NUMERIC) (
             SFUNC = CDB_WeightedMeanS,
             FINALFUNC = CDB_WeightedMeanF,
             STYPE = Numeric[],
             INITCOND = "{0.0,0.0,0.0}" 
         );
+    END IF;
+END
+$$ LANGUAGE plpgsql;