diff --git a/src/common/inc/texpr.h b/src/common/inc/texpr.h
index 311f65073367e2b2a2c5e436b4655cf12ef4c02a..2235d2271081054e60898e5ef117d54dc898ce32 100644
--- a/src/common/inc/texpr.h
+++ b/src/common/inc/texpr.h
@@ -65,7 +65,12 @@ struct SSchema;
 #define TSDB_FUNC_SCALAR_CONCAT_WS    (TSDB_FUNC_FLAG_SCALAR | 0x000F)
 #define TSDB_FUNC_SCALAR_CHAR_LENGTH  (TSDB_FUNC_FLAG_SCALAR | 0x0010)
 #define TSDB_FUNC_SCALAR_CAST         (TSDB_FUNC_FLAG_SCALAR | 0x0011)
-#define TSDB_FUNC_SCALAR_MAX_NUM      18
+#define TSDB_FUNC_SCALAR_LOWER        (TSDB_FUNC_FLAG_SCALAR | 0x0012)
+#define TSDB_FUNC_SCALAR_UPPER        (TSDB_FUNC_FLAG_SCALAR | 0x0013)
+#define TSDB_FUNC_SCALAR_LTRIM        (TSDB_FUNC_FLAG_SCALAR | 0x0014)
+#define TSDB_FUNC_SCALAR_RTRIM        (TSDB_FUNC_FLAG_SCALAR | 0x0015)
+#define TSDB_FUNC_SCALAR_SUBSTR       (TSDB_FUNC_FLAG_SCALAR | 0x0016)
+#define TSDB_FUNC_SCALAR_MAX_NUM      23
 
 #define TSDB_FUNC_SCALAR_NAME_MAX_LEN 16
 
diff --git a/src/common/src/texpr.c b/src/common/src/texpr.c
index db3bec2ddfeee60a90df33cae4c9770bfdb7c46f..1fe05c232fb5253e5d45d8a6fee063075398c4d3 100644
--- a/src/common/src/texpr.c
+++ b/src/common/src/texpr.c
@@ -33,6 +33,8 @@ static int32_t exprValidateMathNode(tExprNode *pExpr);
 static int32_t exprValidateStringConcatNode(tExprNode *pExpr);
 static int32_t exprValidateStringConcatWsNode(tExprNode *pExpr);
 static int32_t exprValidateStringLengthNode(tExprNode *pExpr);
+static int32_t exprValidateStringLowerUpperTrimNode(char* msgBuf, tExprNode *pExpr);
+static int32_t exprValidateStringSubstrNode(char* msgBuf, tExprNode *pExpr);
 static int32_t exprValidateCastNode(char* msgbuf, tExprNode *pExpr);
 
 static int32_t exprInvalidOperationMsg(char *msgbuf, const char *msg) {
@@ -77,6 +79,15 @@ int32_t exprTreeValidateFunctionNode(char* msgbuf, tExprNode *pExpr) {
     case TSDB_FUNC_SCALAR_CONCAT_WS: {
       return exprValidateStringConcatWsNode(pExpr);
     }
+    case TSDB_FUNC_SCALAR_LOWER:
+    case TSDB_FUNC_SCALAR_UPPER:
+    case TSDB_FUNC_SCALAR_LTRIM:
+    case TSDB_FUNC_SCALAR_RTRIM: {
+      return exprValidateStringLowerUpperTrimNode(msgbuf, pExpr);
+    }
+    case TSDB_FUNC_SCALAR_SUBSTR: {
+      return exprValidateStringSubstrNode(msgbuf, pExpr);
+    }
 
     default:
       break;
@@ -1042,6 +1053,58 @@ int32_t exprValidateStringLengthNode(tExprNode *pExpr) {
   return TSDB_CODE_SUCCESS;
 }
 
+int32_t exprValidateStringLowerUpperTrimNode(char* msgBuf, tExprNode *pExpr) {
+  if (pExpr->_func.numChildren != 1) {
+    return TSDB_CODE_TSC_INVALID_OPERATION;
+  }
+
+  tExprNode* child1 = pExpr->_func.pChildren[0];
+
+  if (child1->nodeType == TSQL_NODE_VALUE) {
+    child1->resultType = (int16_t)child1->pVal->nType;
+    child1->resultBytes = (int16_t)(child1->pVal->nLen + VARSTR_HEADER_SIZE);
+  }
+
+  if (!IS_VAR_DATA_TYPE(child1->resultType)) {
+    return TSDB_CODE_TSC_INVALID_OPERATION;
+  }
+
+  pExpr->resultType = child1->resultType;
+  pExpr->resultBytes = child1->resultBytes;
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t exprValidateStringSubstrNode(char* msgBuf, tExprNode *pExpr) {
+  if (pExpr->_func.numChildren != 2 || pExpr->_func.numChildren != 3) {
+    return TSDB_CODE_TSC_INVALID_OPERATION;
+  }
+
+  tExprNode* child1 = pExpr->_func.pChildren[0];
+
+  if (child1->nodeType == TSQL_NODE_VALUE) {
+    child1->resultType = (int16_t)child1->pVal->nType;
+    child1->resultBytes = (int16_t)(child1->pVal->nLen + VARSTR_HEADER_SIZE);
+  }
+
+  if (!IS_VAR_DATA_TYPE(child1->resultType)) {
+    return TSDB_CODE_TSC_INVALID_OPERATION;
+  }
+
+  tExprNode* pos = pExpr->_func.pChildren[1];
+  tExprNode* length = (pExpr->_func.numChildren == 3) ? pExpr->_func.pChildren[2] : NULL;
+
+  if (!IS_NUMERIC_TYPE(pos->resultType) ||
+      (length != NULL && !IS_NUMERIC_TYPE(length->resultType))) {
+    return TSDB_CODE_TSC_INVALID_OPERATION;
+  }
+
+  pExpr->resultType = child1->resultType;
+  pExpr->resultBytes = child1->resultBytes;
+
+  return TSDB_CODE_SUCCESS;
+}
+
 int32_t exprValidateCastNode(char* msgbuf, tExprNode *pExpr) {
   const char* msg1 = "invalid param num for cast function";
   const char* msg2 = "the second param should be a valid type name for cast function";
@@ -1409,6 +1472,16 @@ void vectorCharLength(int16_t functionId, tExprOperandInfo *pInputs, int32_t num
   }
 }
 
+void vectorLowerUpperTrimFunc(int16_t functionId, tExprOperandInfo *pInputs, int32_t numInputs, tExprOperandInfo* pOutput, int32_t order) {
+  assert(numInputs == 1);
+  assert(pInputs[0].numOfRows == 1 || pInputs[0].numOfRows == pOutput->numOfRows);
+  
+}
+
+void vectorSubstrFunc(int16_t functionId, tExprOperandInfo *pInputs, int32_t numInputs, tExprOperandInfo* pOutput, int32_t order) {
+
+}
+
 void vectorMathFunc(int16_t functionId, tExprOperandInfo *pInputs, int32_t numInputs, tExprOperandInfo* pOutput, int32_t order)  {
   for (int i = 0; i < numInputs; ++i) {
     assert(pInputs[i].numOfRows == 1 || pInputs[i].numOfRows == pOutput->numOfRows);
@@ -1724,4 +1797,30 @@ tScalarFunctionInfo aScalarFunctions[] = {
         "cast",
         vectorMathFunc
     },
+    {
+        TSDB_FUNC_SCALAR_LOWER,
+        "lower",
+        vectorLowerUpperTrimFunc
+    },
+    {
+        TSDB_FUNC_SCALAR_UPPER,
+        "upper",
+        vectorLowerUpperTrimFunc
+    },
+    {
+        TSDB_FUNC_SCALAR_LTRIM,
+        "ltrim",
+        vectorLowerUpperTrimFunc
+    },
+    {
+        TSDB_FUNC_SCALAR_RTRIM,
+        "rtrim",
+        vectorLowerUpperTrimFunc
+    },
+    {
+        TSDB_FUNC_SCALAR_SUBSTR,
+        "substr",
+        vectorSubstrFunc
+    },
+
 };