added tests improved func

scripts-available/CDB_EqualIntervalBins.sql

@@ -11,23 +11,24 @@
 -- 
 --
 
-CREATE OR REPLACE FUNCTION CDB_EqualIntervalBins ( in_array NUMERIC[], breaks INT) RETURNS NUMERIC[] as $$ 
+CREATE OR REPLACE FUNCTION CDB_EqualIntervalBins ( in_array NUMERIC[], breaks INT ) RETURNS NUMERIC[] as $$
 DECLARE 
     diff numeric;
     min_val numeric;
+    max_val numeric;
     tmp_val numeric;
     i INT := 1;
     reply numeric[];
 BEGIN
-    SELECT (max(e) - min(e)) / breaks::numeric, min(e) INTO diff, min_val FROM (SELECT unnest(in_array) e) x WHERE e is not null;
-    RAISE NOTICE 'diff = %, min_val = %', diff, min_val;
+    SELECT min(e), max(e) INTO min_val, max_val FROM ( SELECT unnest(in_array) e ) x WHERE e IS NOT NULL;
+    diff = (max_val - min_val) / breaks::numeric;
     LOOP
-        IF i < breaks + 1 THEN
+        IF i < breaks THEN
             tmp_val = min_val + i::numeric * diff;
-            RAISE NOTICE 'tmp_val = %', tmp_val;
             reply = array_append(reply, tmp_val);
             i := i+1;
         ELSE
+            reply = array_append(reply, max_val);
             EXIT;
         END IF;
     END LOOP;

test/CDB_EqualIntervalBinsTest.sql

@@ -0,0 +1,5 @@
+WITH data AS (
+    SELECT array_agg(x) s FROM generate_series(1,300) x 
+        WHERE x % 5 != 0 AND x % 7 != 0
+    ) 
+SELECT unnest(CDB_EqualIntervalBins(s, 7)) FROM data

test/CDB_EqualIntervalBins_expect

@@ -0,0 +1,7 @@
+43.57142857
+86.14285714
+128.71428571
+171.28571429
+213.85714286
+256.42857143
+299