diff --git a/include/common/ttime.h b/include/common/ttime.h
index ed4d1a9290..4db25d2f71 100644
--- a/include/common/ttime.h
+++ b/include/common/ttime.h
@@ -75,6 +75,7 @@ static FORCE_INLINE int64_t taosGetTimestampToday(int32_t precision) {
 int64_t taosTimeAdd(int64_t t, int64_t duration, char unit, int32_t precision);
 
 int64_t taosTimeTruncate(int64_t ts, const SInterval* pInterval);
+int64_t taosTimeGetIntervalEnd(int64_t ts, const SInterval* pInterval);
 int32_t taosTimeCountIntervalForFill(int64_t skey, int64_t ekey, int64_t interval, char unit, int32_t precision, int32_t order);
 
 int32_t parseAbsoluteDuration(const char* token, int32_t tokenlen, int64_t* ts, char* unit, int32_t timePrecision);
diff --git a/source/common/src/ttime.c b/source/common/src/ttime.c
index 376cfce255..f683baee7c 100644
--- a/source/common/src/ttime.c
+++ b/source/common/src/ttime.c
@@ -888,6 +888,18 @@ int64_t taosTimeTruncate(int64_t ts, const SInterval* pInterval) {
   return start;
 }
 
+// used together with taosTimeTruncate. when offset is great than zero, slide-start/slide-end is the anchor point
+int64_t taosTimeGetIntervalEnd(int64_t intervalStart, const SInterval* pInterval) {
+  if (pInterval->offset > 0) {
+    int64_t slideStart = taosTimeAdd(intervalStart, -1 * pInterval->offset, pInterval->offsetUnit, pInterval->precision);
+    int64_t end = taosTimeAdd(slideStart, pInterval->interval, pInterval->intervalUnit, pInterval->precision) - 1;
+    int64_t result = taosTimeAdd(end, pInterval->offset, pInterval->offsetUnit, pInterval->precision);
+    return result;
+  } else {
+    int64_t result = taosTimeAdd(intervalStart, pInterval->interval, pInterval->intervalUnit, pInterval->precision) - 1;
+    return result;
+  }
+}
 // internal function, when program is paused in debugger,
 // one can call this function from debugger to print a
 // timestamp as human readable string, for example (gdb):
diff --git a/source/libs/executor/src/executil.c b/source/libs/executor/src/executil.c
index b713b9b112..019483a015 100644
--- a/source/libs/executor/src/executil.c
+++ b/source/libs/executor/src/executil.c
@@ -1838,7 +1838,7 @@ static STimeWindow doCalculateTimeWindow(int64_t ts, SInterval* pInterval) {
   STimeWindow w = {0};
 
   w.skey = taosTimeTruncate(ts, pInterval);
-  w.ekey = taosTimeAdd(w.skey, pInterval->interval, pInterval->intervalUnit, pInterval->precision) - 1;
+  w.ekey = taosTimeGetIntervalEnd(w.skey, pInterval);
   return w;
 }
 
diff --git a/source/libs/executor/src/executorInt.c b/source/libs/executor/src/executorInt.c
index cb4988c31f..ff4d3d0d27 100644
--- a/source/libs/executor/src/executorInt.c
+++ b/source/libs/executor/src/executorInt.c
@@ -449,13 +449,7 @@ STimeWindow getAlignQueryTimeWindow(const SInterval* pInterval, int64_t key) {
    * if the realSkey > INT64_MAX - pInterval->interval, the query duration between
    * realSkey and realEkey must be less than one interval.Therefore, no need to adjust the query ranges.
    */
-  if (pInterval->offset > 0) {
-    int64_t slideStart = taosTimeAdd(win.skey, -1 * pInterval->offset, pInterval->offsetUnit, pInterval->precision);
-    int64_t slideEnd = taosTimeAdd(slideStart, pInterval->interval, pInterval->intervalUnit, pInterval->precision) - 1;
-    win.ekey = taosTimeAdd(slideEnd, pInterval->offset, pInterval->offsetUnit, pInterval->precision);
-  } else {
-    win.ekey = taosTimeAdd(win.skey, pInterval->interval, pInterval->intervalUnit, pInterval->precision) - 1;
-  }
+  win.ekey = taosTimeGetIntervalEnd(win.skey, pInterval);
   if (win.ekey < win.skey) {
     win.ekey = INT64_MAX;
   }
diff --git a/source/libs/executor/src/timewindowoperator.c b/source/libs/executor/src/timewindowoperator.c
index afe1921d30..c459e4d8b9 100644
--- a/source/libs/executor/src/timewindowoperator.c
+++ b/source/libs/executor/src/timewindowoperator.c
@@ -450,7 +450,7 @@ int32_t getNextQualifiedWindow(SInterval* pInterval, STimeWindow* pNext, SDataBl
       TSKEY next = primaryKeys[startPos];
       if (pInterval->intervalUnit == 'n' || pInterval->intervalUnit == 'y') {
         pNext->skey = taosTimeTruncate(next, pInterval);
-        pNext->ekey = taosTimeAdd(pNext->skey, pInterval->interval, pInterval->intervalUnit, precision) - 1;
+        pNext->ekey = taosTimeGetIntervalEnd(pNext->skey, pInterval);
       } else {
         pNext->ekey += ((next - pNext->ekey + pInterval->sliding - 1) / pInterval->sliding) * pInterval->sliding;
         pNext->skey = pNext->ekey - pInterval->interval + 1;
@@ -459,7 +459,7 @@ int32_t getNextQualifiedWindow(SInterval* pInterval, STimeWindow* pNext, SDataBl
       TSKEY next = primaryKeys[startPos];
       if (pInterval->intervalUnit == 'n' || pInterval->intervalUnit == 'y') {
         pNext->skey = taosTimeTruncate(next, pInterval);
-        pNext->ekey = taosTimeAdd(pNext->skey, pInterval->interval, pInterval->intervalUnit, precision) - 1;
+        pNext->ekey = taosTimeGetIntervalEnd(pNext->skey, pInterval);
       } else {
         pNext->skey -= ((pNext->skey - next + pInterval->sliding - 1) / pInterval->sliding) * pInterval->sliding;
         pNext->ekey = pNext->skey + pInterval->interval - 1;