Fix last_by returning null row after deleting all table data (#16985)

integration-test/src/test/java/org/apache/iotdb/relational/it/db/it/IoTDBDeletionTableIT.java

@@ -476,6 +476,86 @@ public void testSuccessfullyInvalidateCache() throws SQLException {
     cleanData(4);
   }
 
+  @Test
+  public void testLastByWithTimeShouldReturnNoRowsAfterDeletingAllData() throws SQLException {
+    try (Connection connection = EnvFactory.getEnv().getConnection(BaseEnv.TABLE_SQL_DIALECT);
+        Statement statement = connection.createStatement()) {
+      statement.execute("use test");
+      statement.execute("create table last_by_delete_0(deviceId string tag, s0 int32 field)");
+      statement.execute(
+          "insert into last_by_delete_0(time, deviceId, s0) values (1, 'd0', 1)");
+      statement.execute("flush");
+
+      try (ResultSet resultSet =
+          statement.executeQuery(
+              "select last_by(s0, time) from last_by_delete_0 where deviceId = 'd0'")) {
+        assertTrue(resultSet.next());
+      }
+
+      statement.execute("delete from last_by_delete_0 where deviceId = 'd0'");
+
+      try (ResultSet resultSet =
+          statement.executeQuery(
+              "select last_by(s0, time) from last_by_delete_0 where deviceId = 'd0'")) {
+        assertResultSetEmpty(resultSet);
+      }
+
+      try (ResultSet resultSet =
+          statement.executeQuery(
+              "select last_by(s0, time) from last_by_delete_0 where deviceId = 'd0'")) {
+        assertResultSetEmpty(resultSet);
+      }
+    }
+  }
+
+  @Test
+  public void testThreeArgLastByShouldReturnNoRowsAfterDeletingAllData() throws SQLException {
+    try (Connection connection = EnvFactory.getEnv().getConnection(BaseEnv.TABLE_SQL_DIALECT);
+        Statement statement = connection.createStatement()) {
+      statement.execute("use test");
+      statement.execute("create table last_by_delete_1(deviceId string tag, s0 int32 field)");
+      statement.execute(
+          "insert into last_by_delete_1(time, deviceId, s0) values (1, 'd0', 1)");
+      statement.execute("flush");
+
+      try (ResultSet resultSet =
+          statement.executeQuery(
+              "select last_by(time, s0, time) from last_by_delete_1 where deviceId = 'd0'")) {
+        assertTrue(resultSet.next());
+      }
+
+      statement.execute("delete from last_by_delete_1 where deviceId = 'd0'");
+
+      try (ResultSet resultSet =
+          statement.executeQuery(
+              "select last_by(time, s0, time) from last_by_delete_1 where deviceId = 'd0'")) {
+        assertResultSetEmpty(resultSet);
+      }
+
+      try (ResultSet resultSet =
+          statement.executeQuery(
+              "select last_by(time, s0, time) from last_by_delete_1 where deviceId = 'd0'")) {
+        assertResultSetEmpty(resultSet);
+      }
+    }
+  }
+
+  private void assertResultSetEmpty(ResultSet resultSet) throws SQLException {
+    if (!resultSet.next()) {
+      return;
+    }
+
+    StringBuilder rowBuilder = new StringBuilder();
+    int columnCount = resultSet.getMetaData().getColumnCount();
+    for (int i = 1; i <= columnCount; i++) {
+      if (i > 1) {
+        rowBuilder.append(", ");
+      }
+      rowBuilder.append(resultSet.getString(i));
+    }
+    fail("Expected no rows, but got: " + rowBuilder);
+  }
+
   @Test
   public void testFullDeleteWithoutWhereClause() throws SQLException {
     prepareData(5, 1);

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/FileLoaderUtils.java

@@ -370,7 +370,7 @@ private static AbstractAlignedTimeSeriesMetadata setModifications(
     // deal with time column
     List<ModEntry> timeModifications =
         context.getPathModifications(
-            resource, alignedPath.getDeviceId(), timeColumnMetadata.getMeasurementId());
+            resource, alignedPath.getDeviceId(), AlignedFullPath.VECTOR_PLACEHOLDER);
     // all rows are deleted, just return null to skip device data in this file
     if (ModificationUtils.isAllDeletedByMods(
         timeModifications,

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/LastQueryAggTableScanOperator.java

@@ -24,6 +24,7 @@
 import org.apache.iotdb.db.queryengine.execution.fragment.DataNodeQueryContext;
 import org.apache.iotdb.db.queryengine.execution.operator.process.last.LastQueryUtil;
 import org.apache.iotdb.db.queryengine.execution.operator.source.relational.aggregation.LastAccumulator;
+import org.apache.iotdb.db.queryengine.execution.operator.source.relational.aggregation.LastByAccumulator;
 import org.apache.iotdb.db.queryengine.execution.operator.source.relational.aggregation.LastByDescAccumulator;
 import org.apache.iotdb.db.queryengine.execution.operator.source.relational.aggregation.LastDescAccumulator;
 import org.apache.iotdb.db.queryengine.execution.operator.source.relational.aggregation.TableAggregator;
@@ -323,7 +324,9 @@ private void buildResultUseLastValuesCache() {
     // when there is no data, no need to append result if the query is GROUP BY or output of
     // aggregator is partial (final operator will produce NULL result)
     if (timeLastValue == EMPTY_PRIMITIVE_TYPE
-        && (groupingKeySize != 0 || tableAggregators.get(0).getStep().isOutputPartial())) {
+        && (groupingKeySize != 0
+            || tableAggregators.get(0).getStep().isOutputPartial()
+            || shouldSkipEmptyLastByResult(currentHitResult))) {
       outputDeviceIndex++;
       currentHitCacheIndex++;
       return;
@@ -706,7 +709,9 @@ private void checkIfUpdated(
 
   @Override
   protected void updateResultTsBlock() {
-    appendAggregationResult();
+    if (!shouldSkipEmptyLastByResult()) {
+      appendAggregationResult();
+    }
 
     if (needUpdateCache && timeIterator.hasCachedTimeRange()) {
       if (lastRowCacheResults != null) {
@@ -723,6 +728,38 @@ protected void updateResultTsBlock() {
     resetTableAggregators();
   }
 
+  private boolean shouldSkipEmptyLastByResult() {
+    if (groupingKeySize != 0 || tableAggregators.isEmpty()) {
+      return false;
+    }
+    for (TableAggregator aggregator : tableAggregators) {
+      if (!(aggregator.getAccumulator() instanceof LastByAccumulator)) {
+        return false;
+      }
+      if (((LastByAccumulator) aggregator.getAccumulator()).hasInitResult()) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  private boolean shouldSkipEmptyLastByResult(TimeValuePair[] currentHitResult) {
+    if (groupingKeySize != 0 || tableAggregators.isEmpty()) {
+      return false;
+    }
+    for (TableAggregator aggregator : tableAggregators) {
+      if (!(aggregator.getAccumulator() instanceof LastByAccumulator)) {
+        return false;
+      }
+    }
+    for (TimeValuePair timeValuePair : currentHitResult) {
+      if (timeValuePair.getValue() != EMPTY_PRIMITIVE_TYPE) {
+        return false;
+      }
+    }
+    return true;
+  }
+
   @Override
   String getNthIdColumnValue(DeviceEntry deviceEntry, int idColumnIndex) {
     // +1 for skipping the table name segment

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/utils/ModificationUtils.java

@@ -140,6 +140,7 @@ private static boolean areAllValueColumnsDeleted(
         for (TimeRange range : valueChunkMetadata.getDeleteIntervalList()) {
           if (range.contains(valueChunkMetadata.getStartTime(), valueChunkMetadata.getEndTime())) {
             valueChunkMetadataList.set(i, null);
+            modified = true;
             currentRemoved = true;
             break;
           } else {