diff --git a/src/common/src/texpr.c b/src/common/src/texpr.c
index 071f3a6d0ec736d6faf4cf5f1347086279c0b19f..fc8872ea70d7bb4e1b0496bc678ed2a5bacf13c2 100644
--- a/src/common/src/texpr.c
+++ b/src/common/src/texpr.c
@@ -2229,15 +2229,15 @@ void vectorMathFunc(int16_t functionId, tExprOperandInfo *pInputs, int32_t numIn
 }
 
 void convertStringToTimestamp(int16_t type, char *inputData, int64_t timePrec, int64_t *timeVal) {
+  int32_t charLen = varDataLen(inputData);
+  char *newColData;
   if (type == TSDB_DATA_TYPE_BINARY) {
-    int32_t charLen = varDataLen(inputData);
-    char *newColData = calloc(1,  charLen + 1);
+    newColData = calloc(1,  charLen + 1);
     memcpy(newColData, varDataVal(inputData), charLen);
     taosParseTime(newColData, timeVal, charLen, timePrec, 0);
     tfree(newColData);
   } else if (type == TSDB_DATA_TYPE_NCHAR) {
-    int32_t charLen = varDataLen(inputData);
-    char *newColData = calloc(1,  charLen / TSDB_NCHAR_SIZE + 1);
+    newColData = calloc(1,  charLen / TSDB_NCHAR_SIZE + 1);
     int len = taosUcs4ToMbs(varDataVal(inputData), charLen, newColData);
     if (len < 0){
       uError("convertStringToTimestamp taosUcs4ToMbs error");