diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index a8e203e79149135b8ebb36e9d1f1b3e0a8c940ea..b5682139e5735125ac5f58ce48bdf35384820db1 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -1285,8 +1285,6 @@ void tscFieldInfoClear(SFieldInfo* pFieldInfo) {
       for(int32_t j = 0; j < pSqlExpr->numOfParams; ++j) {
         tVariantDestroy(&pSqlExpr->param[j]);
       }
-
-      tfree(pInfo->pExpr->pExpr);
     }
   }
   
@@ -1486,6 +1484,7 @@ void tscSqlExprAssign(SExprInfo* dst, const SExprInfo* src) {
   assert(dst != NULL && src != NULL);
 
   *dst = *src;
+  dst->pExpr = exprdup(src->pExpr);
 
   memset(dst->base.param, 0, sizeof(tVariant) * tListLen(dst->base.param));
   for (int32_t j = 0; j < src->base.numOfParams; ++j) {
diff --git a/src/common/inc/texpr.h b/src/common/inc/texpr.h
index acfbffc01e400f8b111ee92b7651bb048c112bd2..a0854ce81b96c5cb3c77614b7f92497cf4c56340 100644
--- a/src/common/inc/texpr.h
+++ b/src/common/inc/texpr.h
@@ -13,8 +13,8 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef TDENGINE_TAST_H
-#define TDENGINE_TAST_H
+#ifndef TDENGINE_TEXPR_H
+#define TDENGINE_TEXPR_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -62,32 +62,32 @@ typedef struct tExprNode {
   uint8_t nodeType;
   union {
     struct {
-      uint8_t optr;             // filter operator
-      uint8_t hasPK;            // 0: do not contain primary filter, 1: contain
-      void *  info;             // support filter operation on this expression only available for leaf node
-
+      uint8_t           optr;   // filter operator
+      uint8_t           hasPK;  // 0: do not contain primary filter, 1: contain
+      void             *info;   // support filter operation on this expression only available for leaf node
       struct tExprNode *pLeft;  // left child pointer
       struct tExprNode *pRight; // right child pointer
     } _node;
-    struct SSchema *pSchema;
-    tVariant *      pVal;
+
+    struct SSchema     *pSchema;
+    tVariant           *pVal;
   };
 } tExprNode;
 
 typedef struct SExprTraverseSupp {
   __result_filter_fn_t   nodeFilterFn;
   __do_filter_suppl_fn_t setupInfoFn;
-  void *                 pExtInfo;
+  void                  *pExtInfo;
 } SExprTraverseSupp;
 
 void tExprTreeDestroy(tExprNode *pNode, void (*fp)(void *));
 
+void exprTreeToBinary(SBufferWriter* bw, tExprNode* pExprTree);
 tExprNode* exprTreeFromBinary(const void* data, size_t size);
 tExprNode* exprTreeFromTableName(const char* tbnameCond);
+tExprNode* exprdup(tExprNode* pTree);
 
-void exprTreeToBinary(SBufferWriter* bw, tExprNode* pExprTree);
-
-bool exprTreeApplayFilter(tExprNode *pExpr, const void *pItem, SExprTraverseSupp *param);
+bool exprTreeApplyFilter(tExprNode *pExpr, const void *pItem, SExprTraverseSupp *param);
 
 typedef void (*_arithmetic_operator_fn_t)(void *left, int32_t numLeft, int32_t leftType, void *right, int32_t numRight,
                                           int32_t rightType, void *output, int32_t order);
@@ -99,4 +99,4 @@ void arithmeticTreeTraverse(tExprNode *pExprs, int32_t numOfRows, char *pOutput,
 }
 #endif
 
-#endif  // TDENGINE_TAST_H
+#endif  // TDENGINE_TEXPR_H
diff --git a/src/common/src/texpr.c b/src/common/src/texpr.c
index 1008c4cf8f77ca77f59a57aea189cdebef9c9129..4334a0de263e9857385222462724d4b8c758593e 100644
--- a/src/common/src/texpr.c
+++ b/src/common/src/texpr.c
@@ -15,6 +15,7 @@
 
 #include "os.h"
 
+#include "texpr.h"
 #include "exception.h"
 #include "taosdef.h"
 #include "taosmsg.h"
@@ -145,25 +146,25 @@ static void doExprTreeDestroy(tExprNode **pExpr, void (*fp)(void *)) {
   *pExpr = NULL;
 }
 
-bool exprTreeApplayFilter(tExprNode *pExpr, const void *pItem, SExprTraverseSupp *param) {
+bool exprTreeApplyFilter(tExprNode *pExpr, const void *pItem, SExprTraverseSupp *param) {
   tExprNode *pLeft  = pExpr->_node.pLeft;
   tExprNode *pRight = pExpr->_node.pRight;
 
   //non-leaf nodes, recursively traverse the expression tree in the post-root order
   if (pLeft->nodeType == TSQL_NODE_EXPR && pRight->nodeType == TSQL_NODE_EXPR) {
     if (pExpr->_node.optr == TSDB_RELATION_OR) {  // or
-      if (exprTreeApplayFilter(pLeft, pItem, param)) {
+      if (exprTreeApplyFilter(pLeft, pItem, param)) {
         return true;
       }
 
       // left child does not satisfy the query condition, try right child
-      return exprTreeApplayFilter(pRight, pItem, param);
+      return exprTreeApplyFilter(pRight, pItem, param);
     } else {  // and
-      if (!exprTreeApplayFilter(pLeft, pItem, param)) {
+      if (!exprTreeApplyFilter(pLeft, pItem, param)) {
         return false;
       }
 
-      return exprTreeApplayFilter(pRight, pItem, param);
+      return exprTreeApplyFilter(pRight, pItem, param);
     }
   }
 
@@ -463,3 +464,28 @@ tExprNode* exprTreeFromTableName(const char* tbnameCond) {
   CLEANUP_EXECUTE_TO(anchor, false);
   return expr;
 }
+
+tExprNode* exprdup(tExprNode* pTree) {
+  if (pTree == NULL) {
+    return NULL;
+  }
+
+  tExprNode* pNode = calloc(1, sizeof(tExprNode));
+  if (pTree->nodeType == TSQL_NODE_EXPR) {
+    tExprNode* pLeft  = exprdup(pTree->_node.pLeft);
+    tExprNode* pRight = exprdup(pTree->_node.pRight);
+
+    pNode->nodeType     = TSQL_NODE_EXPR;
+    pNode->_node.pLeft  = pLeft;
+    pNode->_node.pRight = pRight;
+  } else if (pTree->nodeType == TSQL_NODE_VALUE) {
+    pNode->pVal = calloc(1, sizeof(tVariant));
+    tVariantAssign(pNode->pVal, pTree->pVal);
+  } else if (pTree->nodeType == TSQL_NODE_COL) {
+    pNode->pSchema = calloc(1, sizeof(SSchema));
+    *pNode->pSchema = *pTree->pSchema;
+  }
+
+  return pNode;
+}
+
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index 648b6d3617a53b004d93add220d007fa228f7076..91491ac2441007e634e6009abab7b56980eeaaf0 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -3428,7 +3428,7 @@ static void applyFilterToSkipListNode(SSkipList *pSkipList, tExprNode *pExpr, SA
   // Scan each node in the skiplist by using iterator
   while (tSkipListIterNext(iter)) {
     SSkipListNode *pNode = tSkipListIterGet(iter);
-    if (exprTreeApplayFilter(pExpr, pNode, param)) {
+    if (exprTreeApplyFilter(pExpr, pNode, param)) {
       taosArrayPush(pResult, &(SL_GET_NODE_DATA(pNode)));
     }
   }