fix(query): check if table exists during creating lastrow reader.

source/dnode/vnode/inc/vnode.h

@@ -136,8 +136,7 @@ int64_t tsdbGetNumOfRowsInMemTable(STsdbReader *pHandle);
 void   *tsdbGetIdx(SMeta *pMeta);
 void   *tsdbGetIvtIdx(SMeta *pMeta);
 
-int32_t tsdbLastRowReaderOpen(void *pVnode, int32_t type, SArray *pTableIdList, int32_t *colId, int32_t numOfCols,
-                              void **pReader);
+int32_t tsdbLastRowReaderOpen(void *pVnode, int32_t type, SArray *pTableIdList, int32_t numOfCols, void **pReader);
 int32_t tsdbRetrieveLastRow(void *pReader, SSDataBlock *pResBlock, const int32_t *slotIds);
 int32_t tsdbLastrowReaderClose(void *pReader);
 int32_t tsdbGetTableSchema(SVnode* pVnode, int64_t uid, STSchema** pSchema, int64_t* suid);

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

@@ -70,6 +70,11 @@ int32_t tsdbLastRowReaderOpen(void* pVnode, int32_t type, SArray* pTableIdList,
   p->numOfCols = numOfCols;
   p->transferBuf = taosMemoryCalloc(p->numOfCols, POINTER_BYTES);
 
+  if (taosArrayGetSize(pTableIdList) == 0) {
+    *pReader = p;
+    return TSDB_CODE_SUCCESS;
+  }
+
   STableKeyInfo* pKeyInfo = taosArrayGet(pTableIdList, 0);
   p->pSchema = metaGetTbTSchema(p->pVnode->pMeta, pKeyInfo->uid, -1);
   p->pTableList = pTableIdList;