diff --git a/src/client/src/tscSyntaxtreefunction.c b/src/client/src/tscSyntaxtreefunction.c
index 1d82b0f239572676c204025fe535704c192e4da6..3e263af982c474a478d3f825c761cd24dcdb249f 100644
--- a/src/client/src/tscSyntaxtreefunction.c
+++ b/src/client/src/tscSyntaxtreefunction.c
@@ -312,7 +312,7 @@ void calc_fn_i32_i32_sub(void *left, void *right, int32_t numLeft, int32_t numRi
   if (numLeft == numRight) {
     for (; i >= 0 && i < numRight; i += step, pOutput += 1) {
       if (isNull((char *)&(pLeft[i]), TSDB_DATA_TYPE_INT) || isNull((char *)&(pRight[i]), TSDB_DATA_TYPE_INT)) {
-        setNull((char *)&(pOutput[i]), TSDB_DATA_TYPE_DOUBLE, tDataTypeDesc[TSDB_DATA_TYPE_DOUBLE].nSize);
+        setNull((char *)&(pOutput), TSDB_DATA_TYPE_DOUBLE, tDataTypeDesc[TSDB_DATA_TYPE_DOUBLE].nSize);
         continue;
       }
       *pOutput = (double)pLeft[i] - pRight[i];