with loop but not fine

secondDbSteps.r

@@ -1,16 +1,27 @@
 library(DBI)
 library(tidyr)
+library(dplyr)
+library(lubridate)
+library(R.utils)
 
 con <- dbConnect(RPostgres::Postgres(), 
                  dbname='mainscnt', 
-                 host='172.16.10.27', 
+                 host='db.mainscnt.eu', 
                  user='wn')
 
-START <- "2021-08-02T14:00:00.0Z"
+
-END <- "2021-08-02T15:00:00.0Z"
+START <- "2021-08-03 00:00:00"
+INTERVAL <- 3600
+
+for (offset in 0:23) {
+  startDate <- ymd_hms(START) + INTERVAL * offset
+  endDate <- startDate + INTERVAL
+
+  startStr <- strftime(startDate, "%Y-%m-%d %H:%M:%S", tz="UTC")
+  endStr <- strftime(endDate, "%Y-%m-%d %H:%M:%S", tz="UTC")
   
   res <-dbSendQuery(con, "select time, location, freq from mainsfrequency where valid=1 and time >= $1 and time < $2")
-dbBind(res, list(START, END))
+  dbBind(res, list(startStr, endStr))
   frequencies <- dbFetch(res)
   dbClearResult(res)
   
@@ -19,6 +30,7 @@ freq_wide <- frequencies %>%
                 values_from = freq, 
                 values_fn = mean)
   
+  freq_wide$Linz_AT <- freq_wide$Linz_AT + 0.002
   
   THRESHOLD <- 0.5
   
@@ -40,6 +52,7 @@ freq_wide <- freq_wide %>%
                      na.rm=TRUE))
   
   # print(summary(freq_wide))
-print(sum(freq_wide$mad) / length(freq_wide$mad))
+  printf("start: %s, end: %s, mad/cnt: %f\n", startStr, endStr, sum(freq_wide$mad) / length(freq_wide$mad))
+}
   
 dbDisconnect(con)