From 1c5fa54c8f503e97f120471226070c4ece389cce Mon Sep 17 00:00:00 2001
From: Wolfgang Hottgenroth <w.hottgenroth@krohne.com>
Date: Wed, 26 May 2021 14:43:04 +0200
Subject: [PATCH] total_energy

---
 function_total_energy_by_day_and_device.sql | 126 ++++++++++++++++----
 1 file changed, 100 insertions(+), 26 deletions(-)

diff --git a/function_total_energy_by_day_and_device.sql b/function_total_energy_by_day_and_device.sql
index 956a68e..a144f26 100644
--- a/function_total_energy_by_day_and_device.sql
+++ b/function_total_energy_by_day_and_device.sql
@@ -1,36 +1,110 @@
-create or replace function total_energy_by_day_and_device(p_day date, p_device varchar)
-  returns double precision
+create table rt_totalizer_result (
+  day date,
+  device text,
+  total double precision
+);
+
+select total_energy_by_day_and_device('2021-05-01','2021-05-10','Computer');
+
+create or replace function total_energy_by_day_and_device(p_start_day date, p_end_say date, p_device varchar)
+  returns setof rt_totalizer_result 
   language plpgsql
   as $$
   declare
     v_firstEnergy double precision;
     v_lastEnergy double precision;
     v_total double precision;
+    v_day date;
+    v_result rt_totalizer_result%rowtype;
   begin
-    select energy
-      into v_lastEnergy
-      from power_measurement_t
-        where time = (
-                       select max(time)
-                         from power_measurement_t
-                         where time between p_day + time '00:00' and p_day + time '00:00' + interval '24h' and
-                               deviceid = p_device and
-                               status = 'Ok'
-                     ) and
-              deviceid = p_device;
-    select energy
-      into v_firstEnergy
-      from power_measurement_t
-        where time = (
-                       select min(time)
-                         from power_measurement_t
-                         where time between p_day + time '00:00' and p_day + time '00:00' + interval '24h' and 
-                               deviceid = p_device and 
-                               status = 'Ok'
-                     ) and
-              deviceid = p_device;
-    v_total := v_lastEnergy - v_firstEnergy;
-    return v_total;
+    v_day := p_start_day;
+    loop
+      select energy
+        into v_lastEnergy
+        from power_measurement_t
+          where time = (
+                        select max(time)
+                          from power_measurement_t
+                          where time between v_day + time '00:00' and v_day + time '00:00' + interval '24h' and
+                                deviceid = p_device and
+                                status = 'Ok'
+                      ) and
+                deviceid = p_device;
+      select energy
+        into v_firstEnergy
+        from power_measurement_t
+          where time = (
+                        select min(time)
+                          from power_measurement_t
+                          where time between v_day + time '00:00' and v_day + time '00:00' + interval '24h' and 
+                                deviceid = p_device and 
+                                status = 'Ok'
+                      ) and
+                deviceid = p_device;
+      v_total := v_lastEnergy - v_firstEnergy;
+      
+      v_result.day := v_day;
+      v_result.device := p_device;
+      v_result.total := v_total;
+      return next v_result;
+      v_day := v_day + interval '1 day';
+      exit when v_day > p_end_say;
+    end loop;
+    return;
+  end;
+$$;
+
+
+select total_energy('2021-05-01','2021-05-10');
+
+create or replace function total_energy(p_start_day date, p_end_say date)
+  returns setof rt_totalizer_result 
+  language plpgsql
+  as $$
+  declare
+    v_firstEnergy double precision;
+    v_lastEnergy double precision;
+    v_total double precision;
+    v_day date;
+    v_deviceid text;
+    v_result rt_totalizer_result%rowtype;
+  begin
+    for v_deviceid in select distinct deviceid from power_measurement_t loop
+      v_day := p_start_day;
+      loop
+        select energy
+          into v_lastEnergy
+          from power_measurement_t
+            where time = (
+                          select max(time)
+                            from power_measurement_t
+                            where time between v_day + time '00:00' and v_day + time '00:00' + interval '24h' and
+                                  deviceid = v_deviceid and
+                                  status = 'Ok'
+                        ) and
+                  deviceid = v_deviceid;
+        select energy
+          into v_firstEnergy
+          from power_measurement_t
+            where time = (
+                          select min(time)
+                            from power_measurement_t
+                            where time between v_day + time '00:00' and v_day + time '00:00' + interval '24h' and 
+                                  deviceid = v_deviceid and 
+                                  status = 'Ok'
+                        ) and
+                  deviceid = v_deviceid;
+        v_total := v_lastEnergy - v_firstEnergy;
+        
+        v_result.day := v_day;
+        v_result.device := v_deviceid;
+        v_result.total := v_total;
+        return next v_result;
+        v_day := v_day + interval '1 day';
+        exit when v_day > p_end_say;
+      end loop;
+    end loop;
+    return;
   end;
 $$;