diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index 0eda49b1f40876f695594e80874c60407e1ca45c..481a0a4d22972e98e96654f5e85e766b8ddd6932 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -168,7 +168,8 @@ void    tscFieldInfoClear(SFieldInfo* pFieldInfo);
 
 static FORCE_INLINE int32_t tscNumOfFields(SQueryInfo* pQueryInfo) { return pQueryInfo->fieldsInfo.numOfOutput; }
 
-int32_t tscFieldInfoCompare(const SFieldInfo* pFieldInfo1, const SFieldInfo* pFieldInfo2);
+int32_t tscFieldInfoCompare(const SFieldInfo* pFieldInfo1, const SFieldInfo* pFieldInfo2, int32_t *diffSize);
+int32_t tscFieldInfoSetSize(const SFieldInfo* pFieldInfo1, const SFieldInfo* pFieldInfo2);
 
 void addExprParams(SSqlExpr* pExpr, char* argument, int32_t type, int32_t bytes);
 
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 5ad372f633a5ab3973acdc6b2290ae4e01e8849b..4cf1423c4311a8959491e0296749283a7d8114c4 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -642,17 +642,25 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       // set the command/global limit parameters from the first subclause to the sqlcmd object
       SQueryInfo* pQueryInfo1 = tscGetQueryInfoDetail(pCmd, 0);
       pCmd->command = pQueryInfo1->command;
-
+      int32_t diffSize = 0;
+      
       // if there is only one element, the limit of clause is the limit of global result.
       for (int32_t i = 1; i < pCmd->numOfClause; ++i) {
         SQueryInfo* pQueryInfo2 = tscGetQueryInfoDetail(pCmd, i);
 
-        int32_t ret = tscFieldInfoCompare(&pQueryInfo1->fieldsInfo, &pQueryInfo2->fieldsInfo);
+        int32_t ret = tscFieldInfoCompare(&pQueryInfo1->fieldsInfo, &pQueryInfo2->fieldsInfo, &diffSize);
         if (ret != 0) {
           return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
         }
       }
 
+      if (diffSize) {
+        for (int32_t i = 1; i < pCmd->numOfClause; ++i) {
+          SQueryInfo* pQueryInfo2 = tscGetQueryInfoDetail(pCmd, i);        
+          tscFieldInfoSetSize(&pQueryInfo1->fieldsInfo, &pQueryInfo2->fieldsInfo);
+        }
+      }
+
       pCmd->parseFinished = 1;
       return TSDB_CODE_SUCCESS;  // do not build query message here
     }
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index fa9e53b0a6c962104a09bef63cc113ccc5ee5dd8..e8d7d5d03cbdd3c90aef20dd1588700e37fff3f8 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -1098,7 +1098,7 @@ int16_t tscFieldInfoGetOffset(SQueryInfo* pQueryInfo, int32_t index) {
   return pInfo->pSqlExpr->offset;
 }
 
-int32_t tscFieldInfoCompare(const SFieldInfo* pFieldInfo1, const SFieldInfo* pFieldInfo2) {
+int32_t tscFieldInfoCompare(const SFieldInfo* pFieldInfo1, const SFieldInfo* pFieldInfo2, int32_t *diffSize) {
   assert(pFieldInfo1 != NULL && pFieldInfo2 != NULL);
 
   if (pFieldInfo1->numOfOutput != pFieldInfo2->numOfOutput) {
@@ -1110,15 +1110,36 @@ int32_t tscFieldInfoCompare(const SFieldInfo* pFieldInfo1, const SFieldInfo* pFi
     TAOS_FIELD* pField2 = tscFieldInfoGetField((SFieldInfo*) pFieldInfo2, i);
 
     if (pField1->type != pField2->type ||
-        pField1->bytes != pField2->bytes ||
         strcasecmp(pField1->name, pField2->name) != 0) {
       return 1;
     }
+
+    if (pField1->bytes != pField2->bytes) {
+      *diffSize = 1;
+
+      if (pField2->bytes > pField1->bytes) {
+        pField1->bytes = pField2->bytes;
+      }
+    }
+  }
+
+  return 0;
+}
+
+int32_t tscFieldInfoSetSize(const SFieldInfo* pFieldInfo1, const SFieldInfo* pFieldInfo2) {
+  assert(pFieldInfo1 != NULL && pFieldInfo2 != NULL);
+
+  for (int32_t i = 0; i < pFieldInfo1->numOfOutput; ++i) {
+    TAOS_FIELD* pField1 = tscFieldInfoGetField((SFieldInfo*) pFieldInfo1, i);
+    TAOS_FIELD* pField2 = tscFieldInfoGetField((SFieldInfo*) pFieldInfo2, i);
+
+    pField2->bytes = pField1->bytes;
   }
 
   return 0;
 }
 
+
 int32_t tscGetResRowLength(SArray* pExprList) {
   size_t num = taosArrayGetSize(pExprList);
   if (num == 0) {
@@ -2682,7 +2703,13 @@ void tscTryQueryNextClause(SSqlObj* pSql, __async_cb_func_t fp) {
 
   //backup the total number of result first
   int64_t num = pRes->numOfTotal + pRes->numOfClauseTotal;
+
+
+  // DON't free final since it may be recoreded and used later in APP
+  TAOS_FIELD* finalBk = pRes->final;
+  pRes->final = NULL;
   tscFreeSqlResult(pSql);
+  pRes->final = finalBk;
   
   pRes->numOfTotal = num;
   
diff --git a/tests/script/general/parser/union.sim b/tests/script/general/parser/union.sim
index 6d3446d1c83abcc88e15b61efacdd95d070229e4..0cd3cba84d5843a423440e55db2bb6f1df946e06 100644
--- a/tests/script/general/parser/union.sim
+++ b/tests/script/general/parser/union.sim
@@ -139,6 +139,34 @@ if $data10 != 1 then
   return -1
 endi
 
+sql select 'ab' as options from union_tb1 limit 1 union all select 'dd' as options from union_tb0 limit 1;
+if $rows != 2 then
+  return -1
+endi
+
+if $data00 != @ab@ then
+  return -1
+endi
+
+if $data10 != @dd@ then
+  return -1
+endi
+
+
+sql select 'ab' as options from union_tb1 limit 1 union all select '1234567' as options from union_tb0 limit 1;
+if $rows != 2 then
+  return -1
+endi
+
+if $data00 != @ab@ then
+  return -1
+endi
+
+if $data10 != @1234567@ then
+  return -1
+endi
+
+
 # mixed order
 sql select ts, c1 from union_tb1 order by ts asc limit 10 union all select ts, c1 from union_tb0 order by ts desc limit 2 union all select ts, c1 from union_tb2 order by ts asc limit 10
 if $rows != 22 then