diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index d8524c3e03a615a250eac3f72f75c72b8f209c84..9426303a7c3327cc2ef62ad23c3889c58b8ec185 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -1276,7 +1276,7 @@ static bool validateTagParams(SArray* pTagsList, SArray* pFieldList, SSqlCmd* pC
   const char* msg1 = "invalid number of tag columns";
   const char* msg2 = "tag length too long";
   const char* msg3 = "duplicated column names";
-  const char* msg4 = "timestamp not allowed in tags";
+  //const char* msg4 = "timestamp not allowed in tags";
   const char* msg5 = "invalid data type in tags";
   const char* msg6 = "invalid tag name";
   const char* msg7 = "invalid binary/nchar tag length";
@@ -1292,10 +1292,10 @@ static bool validateTagParams(SArray* pTagsList, SArray* pFieldList, SSqlCmd* pC
   for (int32_t i = 0; i < numOfTags; ++i) {
     TAOS_FIELD* p = taosArrayGet(pTagsList, i);
 
-    if (p->type == TSDB_DATA_TYPE_TIMESTAMP) {
-      invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg4);
-      return false;
-    }
+    //if (p->type == TSDB_DATA_TYPE_TIMESTAMP) {
+    //  invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg4);
+    //  return false;
+    //}
 
     if (!isValidDataType(p->type)) {
       invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg5);
@@ -1353,7 +1353,7 @@ static bool validateTagParams(SArray* pTagsList, SArray* pFieldList, SSqlCmd* pC
  * tags name /column name is truncated in sql.y
  */
 bool validateOneTags(SSqlCmd* pCmd, TAOS_FIELD* pTagField) {
-  const char* msg1 = "timestamp not allowed in tags";
+  //const char* msg1 = "timestamp not allowed in tags";
   const char* msg2 = "duplicated column names";
   const char* msg3 = "tag length too long";
   const char* msg4 = "invalid tag name";
@@ -1376,10 +1376,10 @@ bool validateOneTags(SSqlCmd* pCmd, TAOS_FIELD* pTagField) {
   }
 
   // no timestamp allowable
-  if (pTagField->type == TSDB_DATA_TYPE_TIMESTAMP) {
-    invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg1);
-    return false;
-  }
+  //if (pTagField->type == TSDB_DATA_TYPE_TIMESTAMP) {
+  //  invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg1);
+  //  return false;
+  //}
 
   if ((pTagField->type < TSDB_DATA_TYPE_BOOL) || (pTagField->type > TSDB_DATA_TYPE_UBIGINT)) {
     invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg6);
@@ -8001,8 +8001,24 @@ int32_t exprTreeFromSqlExpr(SSqlCmd* pCmd, tExprNode **pExpr, const tSqlExpr* pS
       *pExpr = calloc(1, sizeof(tExprNode));
       (*pExpr)->nodeType = TSQL_NODE_VALUE;
       (*pExpr)->pVal = calloc(1, sizeof(tVariant));
-      
       tVariantAssign((*pExpr)->pVal, &pSqlExpr->value);
+
+      int32_t type = -1;
+      STableMeta* pTableMeta = tscGetMetaInfo(pQueryInfo, 0)->pTableMeta;
+      if (pCols != NULL) {
+        SColIndex* idx = taosArrayGet(pCols, 0);
+        SSchema* pSchema = tscGetTableColumnSchema(pTableMeta, idx->colIndex);
+        if (pSchema != NULL) {
+          type = pSchema->type; 
+        }
+      }
+      if (type == TSDB_DATA_TYPE_TIMESTAMP) {
+        int32_t ret = setColumnFilterInfoForTimestamp(pCmd, pQueryInfo, (*pExpr)->pVal);
+        if (ret != TSDB_CODE_SUCCESS) {
+          return ret;
+        }
+      }
+      
       return TSDB_CODE_SUCCESS;
     } else if (pSqlExpr->type == SQL_NODE_SQLFUNCTION) {
       // arithmetic expression on the results of aggregation functions
diff --git a/src/common/src/tvariant.c b/src/common/src/tvariant.c
index 33dab51633b244326b0490c6bf7b784bc41fe77f..1168eeb231fec49907b7ced9f019f55af2b085a8 100644
--- a/src/common/src/tvariant.c
+++ b/src/common/src/tvariant.c
@@ -77,6 +77,10 @@ void tVariantCreate(tVariant *pVar, SStrToken *token) {
       pVar->nLen = strRmquote(pVar->pz, token->n);
       break;
     }
+    case TSDB_DATA_TYPE_TIMESTAMP: {
+      pVar->i64 = taosGetTimestamp(TSDB_TIME_PRECISION_NANO);                           
+      break;                             
+    }                            
     
     default: {  // nType == 0 means the null value
       type = TSDB_DATA_TYPE_NULL;
diff --git a/src/query/inc/sql.y b/src/query/inc/sql.y
index fbb59e4a728724fd2fc2638d6d754cf2347350b6..07403699245ff767f17e7d373c8a1eae0b1a9b8a 100644
--- a/src/query/inc/sql.y
+++ b/src/query/inc/sql.y
@@ -433,6 +433,7 @@ tagitem(A) ::= FLOAT(X).        { toTSDBType(X.type); tVariantCreate(&A, &X); }
 tagitem(A) ::= STRING(X).       { toTSDBType(X.type); tVariantCreate(&A, &X); }
 tagitem(A) ::= BOOL(X).         { toTSDBType(X.type); tVariantCreate(&A, &X); }
 tagitem(A) ::= NULL(X).         { X.type = 0; tVariantCreate(&A, &X); }
+tagitem(A) ::= NOW(X).          { X.type = TSDB_DATA_TYPE_TIMESTAMP; tVariantCreate(&A, &X);}
 
 tagitem(A) ::= MINUS(X) INTEGER(Y).{
     X.n += Y.n;
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 395903f75ef4a0cb4626baf9416c17a9b8221052..e6b40f40d681ec274292a1246bb41eef54fb50c9 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -2889,7 +2889,9 @@ void setTagValue(SOperatorInfo* pOperatorInfo, void *pTable, SQLFunctionCtx* pCt
       doSetTagValueInParam(pTable, pLocalExprInfo->base.colInfo.colId, &pCtx[idx].tag, pLocalExprInfo->base.resType,
                            pLocalExprInfo->base.resBytes);
 
-      if (IS_NUMERIC_TYPE(pLocalExprInfo->base.resType) || pLocalExprInfo->base.resType == TSDB_DATA_TYPE_BOOL) {
+      if (IS_NUMERIC_TYPE(pLocalExprInfo->base.resType) 
+          || pLocalExprInfo->base.resType == TSDB_DATA_TYPE_BOOL 
+          || pLocalExprInfo->base.resType == TSDB_DATA_TYPE_TIMESTAMP) {
         memcpy(pRuntimeEnv->tagVal + offset, &pCtx[idx].tag.i64, pLocalExprInfo->base.resBytes);
       } else {
         memcpy(pRuntimeEnv->tagVal + offset, pCtx[idx].tag.pz, pCtx[idx].tag.nLen);