implement hour in date_trunc

h2/src/main/org/h2/util/DateTimeUtils.java

@@ -1484,9 +1484,28 @@ public class DateTimeUtils {
         // Retrieve the dateValue.
         long[] fieldDateAndTime = DateTimeUtils.dateAndTimeFromValue(value);
         long dateValue = fieldDateAndTime[0];
+        long timeNanos = fieldDateAndTime[1];
 
-        // Case where the date has to be truncated to the day.
-        if (timeUnit.equals("DAY")) {
+        long nanoInHours = 3_600_000_000_000l;
+
+        if (timeUnit.equals("HOUR")) {
+
+            long hour = timeNanos / nanoInHours;
+            long hourInNano = hour * nanoInHours;
+
+            if (value instanceof ValueTimestampTimeZone) {
+
+                ValueTimestampTimeZone vTmp = (ValueTimestampTimeZone) value;
+                result = ValueTimestampTimeZone.fromDateValueAndNanos(vTmp.getDateValue(), hourInNano,
+                        vTmp.getTimeZoneOffsetMins());
+
+            } else {
+
+                result = ValueTimestamp.fromDateValueAndNanos(dateValue, hourInNano);
+
+            }
+
+        } else if (timeUnit.equals("DAY")) {
 
             if (value instanceof ValueTimestampTimeZone) {
 
@@ -1505,7 +1524,9 @@ public class DateTimeUtils {
                 result = ValueTimestamp.fromDateValueAndNanos(dateValue, 0);
 
             }
-        } else {
+        }
+
+        else {
 
             // Return an exception for the other possible value (not yet
             // supported).

h2/src/test/org/h2/test/scripts/functions/timeanddate/date_trunc.sql

+
+--
+-- Test time unit 'HOUR'
+--
+
+SELECT DATE_TRUNC('HOUR', time '00:00:00');
+>> 1970-01-01 00:00:00
+
+SELECT DATE_TRUNC('hour', time '00:00:00');
+>> 1970-01-01 00:00:00
+
+SELECT DATE_TRUNC('HOUR', time '15:00:00');
+>> 1970-01-01 15:00:00
+
+SELECT DATE_TRUNC('hour', time '15:00:00');
+>> 1970-01-01 15:00:00
+
+SELECT DATE_TRUNC('HOUR', time '15:14:13');
+>> 1970-01-01 15:00:00
+
+SELECT DATE_TRUNC('hour', time '15:14:13');
+>> 1970-01-01 15:00:00
+
+SELECT DATE_TRUNC('HOUR', date '2015-05-29');
+>> 2015-05-29 00:00:00
+
+SELECT DATE_TRUNC('hour', date '2015-05-29');
+>> 2015-05-29 00:00:00
+
+SELECT DATE_TRUNC('HOUR', date '1970-01-01');
+>> 1970-01-01 00:00:00
+
+SELECT DATE_TRUNC('hour', date '1970-01-01');
+>> 1970-01-01 00:00:00
+
+select DATE_TRUNC('HOUR', timestamp with time zone '2015-05-29 15:14:13');
+>> 2015-05-29 15:00:00+00
+
+select DATE_TRUNC('hour', timestamp with time zone '2015-05-29 15:14:13');
+>> 2015-05-29 15:00:00+00
+
+select DATE_TRUNC('HOUR', timestamp with time zone '2015-05-29 15:14:13-06');
+>> 2015-05-29 15:00:00-06
+
+select DATE_TRUNC('hour', timestamp with time zone '2015-05-29 15:14:13-06');
+>> 2015-05-29 15:00:00-06
+
+select DATE_TRUNC('HOUR', timestamp with time zone '2015-05-29 15:14:13+10');
+>> 2015-05-29 15:00:00+10
+
+select DATE_TRUNC('hour', timestamp with time zone '2015-05-29 15:14:13+10');
+>> 2015-05-29 15:00:00+10
+
+SELECT DATE_TRUNC('hour', timestamp '2015-05-29 15:14:13');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('HOUR', timestamp '2015-05-29 15:14:13');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('hour', timestamp '2015-05-29 15:00:00');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('HOUR', timestamp '2015-05-29 15:00:00');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('hour', timestamp '2015-05-29 00:00:00');
+>> 2015-05-29 00:00:00
+
+SELECT DATE_TRUNC('HOUR', timestamp '2015-05-29 00:00:00');
+>> 2015-05-29 00:00:00
+
+SELECT DATE_TRUNC('hour', '2015-05-29 15:14:13');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('HOUR', '2015-05-29 15:14:13');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('hour', '2015-05-29 15:00:00');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('HOUR', '2015-05-29 15:00:00');
+>> 2015-05-29 15:00:00
+
+SELECT DATE_TRUNC('hour', '2015-05-29 00:00:00');
+>> 2015-05-29 00:00:00
+
+SELECT DATE_TRUNC('HOUR', '2015-05-29 00:00:00');
+>> 2015-05-29 00:00:00
+
+
+-- 
+-- Test time unit 'DAY'
+--
 select DATE_TRUNC('day', time '00:00:00');
 >> 1970-01-01 00:00:00
 
@@ -46,6 +139,10 @@ select DATE_TRUNC('day', '2015-05-29 15:14:13');
 select DATE_TRUNC('DAY', '2015-05-29 15:14:13');
 >> 2015-05-29 00:00:00
 
+
+--
+-- Test unhandled time unit
+--
 SELECT DATE_TRUNC('---', '2015-05-29 15:14:13');
 > exception
 
@@ -73,12 +170,6 @@ SELECT DATE_TRUNC('minute', '2015-05-29 15:14:13');
 SELECT DATE_TRUNC('MINUTE', '2015-05-29 15:14:13');
 > exception
 
-SELECT DATE_TRUNC('hour', '2015-05-29 15:14:13');
-> exception
-
-SELECT DATE_TRUNC('HOUR', '2015-05-29 15:14:13');
-> exception
-
 SELECT DATE_TRUNC('week', '2015-05-29 15:14:13');
 > exception