diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index d9a05973ce..22438e6939 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -1615,26 +1615,27 @@ static int32_t translateSubstr(SFunctionNode* pFunc, char* pErrBuf, int32_t len)
   }
 
   SExprNode* pPara0 = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 0);
-  SExprNode* p1 = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 1);
+  SExprNode* pPara1 = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 1);
 
-  uint8_t para1Type = p1->resType.type;
-  if (!IS_VAR_DATA_TYPE(pPara0->resType.type) || !IS_INTEGER_TYPE(para1Type)) {
+  uint8_t para0Type = pPara0->resType.type;
+  uint8_t para1Type = pPara1->resType.type;
+  if (!IS_VAR_DATA_TYPE(para0Type) || !IS_INTEGER_TYPE(para1Type)) {
     return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
-  if (((SValueNode*)p1)->datum.i < 1) {
+  if (((SValueNode*)pPara1)->datum.i == 0) {
     return invaildFuncParaValueErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
   if (3 == numOfParams) {
-    SExprNode* p2 = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 2);
-    uint8_t    para2Type = p2->resType.type;
+    SExprNode* pPara2 = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 2);
+    uint8_t    para2Type = pPara2->resType.type;
     if (!IS_INTEGER_TYPE(para2Type)) {
       return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
     }
 
-    int64_t v = ((SValueNode*)p1)->datum.i;
-    if (v < 0 || v > INT16_MAX) {
+    int64_t v = ((SValueNode*)pPara2)->datum.i;
+    if (v < 0) {
       return invaildFuncParaValueErrMsg(pErrBuf, len, pFunc->functionName);
     }
   }