fix(query): add check before retrieve data.

source/dnode/vnode/src/tsdb/tsdbRead.c

@@ -1402,7 +1402,7 @@ static int32_t doMergeBufAndFileRows_Rv(STsdbReader* pReader, STableBlockScanInf
   SFileBlockDumpInfo* pDumpInfo = &pReader->status.fBlockDumpInfo;
 
   int64_t tsLast = INT64_MIN;
-  if (pLastBlockReader->lastBlockData.nRow > 0) {
+  if ((pLastBlockReader->lastBlockData.nRow > 0) && hasDataInLastBlock(pLastBlockReader)) {
     tsLast = getCurrentKeyInLastBlock(pLastBlockReader);
   }
 
@@ -1595,7 +1595,10 @@ static int32_t doMergeMultiLevelRowsRv(STsdbReader* pReader, STableBlockScanInfo
   ASSERT(pRow != NULL && piRow != NULL);
 
   SBlockData* pLastBlockData = &pLastBlockReader->lastBlockData;
-  int64_t tsLast = getCurrentKeyInLastBlock(pLastBlockReader);
+  int64_t tsLast = INT64_MIN;
+  if (hasDataInLastBlock(pLastBlockReader)) {
+    tsLast = getCurrentKeyInLastBlock(pLastBlockReader);
+  }
 
   int64_t key = pBlockData->aTSKEY[pDumpInfo->rowIndex];
 
@@ -1617,7 +1620,7 @@ static int32_t doMergeMultiLevelRowsRv(STsdbReader* pReader, STableBlockScanInfo
       minKey = key;
     }
 
-    if (minKey > tsLast && pLastBlockData->nRow > 0) {
+    if (minKey > tsLast && hasDataInLastBlock(pLastBlockReader)) {
       minKey = tsLast;
     }
   } else {
@@ -1634,7 +1637,7 @@ static int32_t doMergeMultiLevelRowsRv(STsdbReader* pReader, STableBlockScanInfo
       minKey = key;
     }
 
-    if (minKey < tsLast && pLastBlockData->nRow > 0) {
+    if (minKey < tsLast && hasDataInLastBlock(pLastBlockReader)) {
       minKey = tsLast;
     }
   }