diff --git a/src/client/src/tscGlobalmerge.c b/src/client/src/tscGlobalmerge.c
index 130abdf4a73ade3951070a100555d15270c265f2..fab1f5123e3e7078d70e21bc269a4161e842ceb9 100644
--- a/src/client/src/tscGlobalmerge.c
+++ b/src/client/src/tscGlobalmerge.c
@@ -967,7 +967,6 @@ SSDataBlock* doGlobalAggregate(void* param, bool* newgroup) {
 
       if (pOperator->pRuntimeEnv->pQueryAttr->order.order == TSDB_ORDER_DESC) {
         SWAP(w->skey, w->ekey, TSKEY);
-        assert(w->skey <= w->ekey);
       }
     }
   }
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 1e23e9e56eeabde993020f0a6c45b81390b33d08..79bb93d596f732a240eee633725ca45e9f5a5bc0 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -2029,6 +2029,7 @@ int32_t validateSelectNodeList(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SArray* pS
   const char* msg6 = "not support distinct mixed with join"; 
   const char* msg7 = "not support distinct mixed with groupby";
   const char* msg8 = "not support distinct in nest query";
+  const char* msg9 = "invalid alias name";
 
   // too many result columns not support order by in query
   if (taosArrayGetSize(pSelNodeList) > TSDB_MAX_COLUMNS) {
@@ -2052,6 +2053,9 @@ int32_t validateSelectNodeList(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SArray* pS
        hasDistinct = (pItem->distinct == true); 
        distIdx     =  hasDistinct ? i : -1;
     }
+    if(pItem->aliasName != NULL && validateColumnName(pItem->aliasName) != TSDB_CODE_SUCCESS){
+      return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg9);
+    }
 
     int32_t type = pItem->pNode->type;
     if (type == SQL_NODE_SQLFUNCTION) {
diff --git a/tests/pytest/query/queryGroupTbname.py b/tests/pytest/query/queryGroupTbname.py
index 095feed52fa7c44e2dd1b98a5f15c7034165b95e..73ee5f0fa8d2f358e34bab3336d6f64364b6af83 100644
--- a/tests/pytest/query/queryGroupTbname.py
+++ b/tests/pytest/query/queryGroupTbname.py
@@ -14,6 +14,7 @@ from util.log import tdLog
 from util.cases import tdCases
 from util.sql import tdSql
 from util.common import tdCom
+import random
 
 class TDTestCase:
     def init(self, conn, logSql):
@@ -47,6 +48,26 @@ class TDTestCase:
         for i in range(100):
             tdSql.query(f'select {table_name_sub1},{table_name_sub2},{table_name_sub3},{table_name_sub4},{table_name_sub5},{table_name_sub6},{table_name_sub7},{table_name_sub8},{table_name_sub9} from {table_name} where tbname in ("{table_name_sub1}","{table_name_sub2}","{table_name_sub3}","{table_name_sub4}","{table_name_sub5}","{table_name_sub6}","{table_name_sub7}","{table_name_sub8}","{table_name_sub9}") and ts >= "1980-01-01 00:00:00.000"')
             tdSql.checkRows(90)
+        
+        # TS-634
+        tdLog.info("test case for bug TS-634")
+        tdSql.execute("create database test")
+        tdSql.execute("use test")
+        tdSql.execute("create table meters (ts TIMESTAMP,voltage INT) TAGS (tableid INT)")
+        tdSql.execute("CREATE TABLE t1 USING meters TAGS (1)")
+        tdSql.execute("CREATE TABLE t2 USING meters TAGS (2)")
+
+        ts = 1605381041000
+        for i in range(10):                
+            tdSql.execute("INSERT INTO t1 values(%d, %d)" % (ts + i, random.randint(0, 100)))
+            tdSql.execute("INSERT INTO t2 values(%d, %d)" % (ts + i, random.randint(0, 100)))
+        
+        tdSql.query("select last_row(*), tbname from meters group by tbname order by ts desc")
+        tdSql.checkRows(2)
+
+        tdSql.execute("INSERT INTO t2 values(now, 2)")
+        tdSql.query("select last_row(*), tbname from meters group by tbname order by ts desc")
+        tdSql.checkRows(2)
 
     def run(self):
         tdSql.prepare()