Esql compare nanos and millis

docs/changelog/118027.yaml

@@ -0,0 +1,6 @@
+pr: 118027
+summary: Esql compare nanos and millis
+area: ES|QL
+type: enhancement
+issues:
+ - 116281

server/src/main/java/org/elasticsearch/common/time/DateUtils.java

@@ -293,6 +293,17 @@ public static long toMilliSeconds(long nanoSecondsSinceEpoch) {
         return nanoSecondsSinceEpoch / 1_000_000;
     }
 
+    public static int compareNanosToMillis(long nanos, long millis) {
+        if (millis < 0) {
+            return 1;
+        }
+        if (millis > MAX_NANOSECOND_IN_MILLIS) {
+            return -1;
+        }
+        long diff = nanos - (millis * 1_000_000);
+        return diff == 0 ? 0 : diff < 0 ? -1 : 1;
+    }
+
     /**
      * Rounds the given utc milliseconds sicne the epoch down to the next unit millis
      *

server/src/test/java/org/elasticsearch/common/time/DateUtilsTests.java

@@ -20,7 +20,10 @@
 import java.time.ZonedDateTime;
 import java.time.temporal.ChronoField;
 
+import static org.elasticsearch.common.time.DateUtils.MAX_MILLIS_BEFORE_MINUS_9999;
+import static org.elasticsearch.common.time.DateUtils.MAX_NANOSECOND_INSTANT;
 import static org.elasticsearch.common.time.DateUtils.clampToNanosRange;
+import static org.elasticsearch.common.time.DateUtils.compareNanosToMillis;
 import static org.elasticsearch.common.time.DateUtils.toInstant;
 import static org.elasticsearch.common.time.DateUtils.toLong;
 import static org.elasticsearch.common.time.DateUtils.toMilliSeconds;
@@ -31,6 +34,35 @@
 
 public class DateUtilsTests extends ESTestCase {
 
+    public void testCompareNanosToMillis() {
+        assertThat(compareNanosToMillis(toLong(Instant.EPOCH), Instant.EPOCH.toEpochMilli()), is(0));
+
+        // millis before epoch
+        assertCompareInstants(
+            randomInstantBetween(Instant.EPOCH, MAX_NANOSECOND_INSTANT),
+            randomInstantBetween(Instant.ofEpochMilli(MAX_MILLIS_BEFORE_MINUS_9999), Instant.ofEpochMilli(-1L))
+        );
+
+        // millis after nanos range
+        assertCompareInstants(
+            randomInstantBetween(Instant.EPOCH, MAX_NANOSECOND_INSTANT),
+            randomInstantBetween(MAX_NANOSECOND_INSTANT.plusMillis(1), Instant.ofEpochMilli(Long.MAX_VALUE))
+        );
+
+        // both in range
+        Instant nanos = randomInstantBetween(Instant.EPOCH, MAX_NANOSECOND_INSTANT);
+        Instant millis = randomInstantBetween(Instant.EPOCH, MAX_NANOSECOND_INSTANT);
+
+        assertCompareInstants(nanos, millis);
+    }
+
+    /**
+     *  check that compareNanosToMillis is consistent with Instant#compare.
+     */
+    private void assertCompareInstants(Instant nanos, Instant millis) {
+        assertThat(compareNanosToMillis(toLong(nanos), millis.toEpochMilli()), equalTo(nanos.compareTo(millis)));
+    }
+
     public void testInstantToLong() {
         assertThat(toLong(Instant.EPOCH), is(0L));
 

x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/EsqlTestUtils.java

@@ -726,7 +726,7 @@ public static Literal randomLiteral(DataType type) {
             case UNSIGNED_LONG, LONG, COUNTER_LONG -> randomLong();
             case DATE_PERIOD -> Period.of(randomIntBetween(-1000, 1000), randomIntBetween(-13, 13), randomIntBetween(-32, 32));
             case DATETIME -> randomMillisUpToYear9999();
-            case DATE_NANOS -> randomLong();
+            case DATE_NANOS -> randomLongBetween(0, Long.MAX_VALUE);
             case DOUBLE, SCALED_FLOAT, COUNTER_DOUBLE -> randomDouble();
             case FLOAT -> randomFloat();
             case HALF_FLOAT -> HalfFloatPoint.sortableShortToHalfFloat(HalfFloatPoint.halfFloatToSortableShort(randomFloat()));