[TD-11983]<fix>: elapsed function second param time_unit should not contain now keyword

src/client/src/tscSQLParser.c

@@ -2727,7 +2727,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
       memset(pExpr->base.aliasName, 0, tListLen(pExpr->base.aliasName));
       getColumnName(pItem, pExpr->base.aliasName, pExpr->base.token,sizeof(pExpr->base.aliasName) - 1);
-      
+
       SColumnList list = createColumnList(1, index.tableIndex, index.columnIndex);
       if (finalResult) {
         int32_t numOfOutput = tscNumOfFields(pQueryInfo);
@@ -2852,6 +2852,10 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
         char val[8] = {0};
 
         int64_t tickPerSec = 0;
+        if (pParamElem[1].pNode->exprToken.type == TK_NOW) {
+          return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg2);
+        }
+
         if ((TSDB_DATA_TYPE_NULL == pParamElem[1].pNode->value.nType) || tVariantDump(&pParamElem[1].pNode->value, (char*) &tickPerSec, TSDB_DATA_TYPE_BIGINT, true) < 0) {
           return TSDB_CODE_TSC_INVALID_OPERATION;
         }
@@ -2866,7 +2870,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
           return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg10);
         } else if (tickPerSec <= 0) {
           return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg16);
-        } 
+        }
 
         tscExprAddParams(&pExpr->base, (char*) &tickPerSec, TSDB_DATA_TYPE_BIGINT, LONG_BYTES);
         if (functionId == TSDB_FUNC_DERIVATIVE) {