diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 25fb2968f7423e06c734f0fc3cebe52b5ed05173..57ae8426ffc4f8ede4ff4191b83b5025acc8da4b 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -5664,7 +5664,6 @@ int32_t doCheckForCreateFromStable(SSqlObj* pSql, SSqlInfo* pInfo) {
     return ret;
   }
 
-  //pTag->dataLen = tagVal - pTag->data;
   return TSDB_CODE_SUCCESS;
 }
 
diff --git a/src/common/src/ttypes.c b/src/common/src/ttypes.c
index 3c63e2deacc88aed967508a6affc44b1bc7d85ca..8ea4fe906aa04b53da0468d874d76894622cc18e 100644
--- a/src/common/src/ttypes.c
+++ b/src/common/src/ttypes.c
@@ -464,6 +464,28 @@ void setNullN(char *val, int32_t type, int32_t bytes, int32_t numOfElems) {
   }
 }
 
+static uint8_t  nullBool = TSDB_DATA_BOOL_NULL;
+static uint8_t  nullTinyInt = TSDB_DATA_TINYINT_NULL;
+static uint16_t nullSmallInt = TSDB_DATA_SMALLINT_NULL;
+static uint32_t nullInt = TSDB_DATA_INT_NULL;
+static uint64_t nullBigInt = TSDB_DATA_BIGINT_NULL;
+static uint32_t nullFloat = TSDB_DATA_FLOAT_NULL;
+static uint64_t nullDouble = TSDB_DATA_DOUBLE_NULL;
+static struct {
+  tstr str;
+  int32_t pad;
+} nullBinary = {.str = {.len = 1}, .pad = 0}, nullNchar = {.str = {.len = 4}, .pad = 0};
+
+static void *nullValues[] = {
+    &nullBool,  &nullTinyInt, &nullSmallInt, &nullInt,    &nullBigInt,
+    &nullFloat, &nullDouble,  &nullBinary,   &nullBigInt, &nullNchar,
+};
+
+void *getNullValue(int32_t type) {
+  assert(type >= TSDB_DATA_TYPE_BOOL && type <= TSDB_DATA_TYPE_NCHAR);
+  return nullValues[type - 1];
+}
+
 void assignVal(char *val, const char *src, int32_t len, int32_t type) {
   switch (type) {
     case TSDB_DATA_TYPE_INT: {
diff --git a/src/inc/taosdef.h b/src/inc/taosdef.h
index ecf78edfd5725b7ae701bbf100d6b422b65f04fc..76ca99c9ad26bb9228cd1d94cf463657bf1a5f8f 100644
--- a/src/inc/taosdef.h
+++ b/src/inc/taosdef.h
@@ -165,6 +165,7 @@ bool isNull(const char *val, int32_t type);
 void setVardataNull(char* val, int32_t type);
 void setNull(char *val, int32_t type, int32_t bytes);
 void setNullN(char *val, int32_t type, int32_t bytes, int32_t numOfElems);
+void* getNullValue(int32_t type);
 
 void assignVal(char *val, const char *src, int32_t len, int32_t type);
 void tsDataSwap(void *pLeft, void *pRight, int32_t type, int32_t size);
diff --git a/src/tsdb/src/tsdbMeta.c b/src/tsdb/src/tsdbMeta.c
index 7851329c470b7b67a68f3484c6a02322da1ba1ab..4f331d8131403732691d0a91a7d5b955244849d4 100644
--- a/src/tsdb/src/tsdbMeta.c
+++ b/src/tsdb/src/tsdbMeta.c
@@ -604,6 +604,10 @@ static char *getTagIndexKey(const void *pData) {
   STSchema *pSchema = tsdbGetTableTagSchema(pTable);
   STColumn *pCol = schemaColAt(pSchema, DEFAULT_TAG_INDEX_COLUMN);
   void *    res = tdGetKVRowValOfCol(pTable->tagVal, pCol->colId);
+  if (res == NULL) {
+    // treat the column as NULL if we cannot find it
+    res = getNullValue(pCol->type);
+  }
   return res;
 }
 
@@ -849,6 +853,7 @@ static int tsdbAddTableIntoIndex(STsdbMeta *pMeta, STable *pTable) {
   STable *pSTable = tsdbGetTableByUid(pMeta, TABLE_SUID(pTable));
   ASSERT(pSTable != NULL);
 
+  printf("pTable = %p, pSTable = %p\n", pTable, pSTable);
   pTable->pSuper = pSTable;
 
   int32_t level = 0;