diff --git a/src/client/src/tscFunctionImpl.c b/src/client/src/tscFunctionImpl.c
index 1356b98c6762e77e338998bfa7e5f4fb57a3b0e5..da575b9354be32c2a79d46ed204df1a860e9d69a 100644
--- a/src/client/src/tscFunctionImpl.c
+++ b/src/client/src/tscFunctionImpl.c
@@ -711,13 +711,16 @@ static int32_t firstDistFuncRequired(SQLFunctionCtx *pCtx, TSKEY start, TSKEY en
   if (pCtx->aOutputBuf == NULL) {
     return BLK_DATA_ALL_NEEDED;
   }
-  
-  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
-  if (pInfo->hasResult != DATA_SET_FLAG) {
-    return BLK_DATA_ALL_NEEDED;
-  } else {  // data in current block is not earlier than current result
-    return (pInfo->ts <= start) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
-  }
+
+  return BLK_DATA_ALL_NEEDED;
+  // TODO pCtx->aOutputBuf is the previous windowRes output buffer, not current unloaded block. so the following filter
+  // is invalid
+//  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
+//  if (pInfo->hasResult != DATA_SET_FLAG) {
+//    return BLK_DATA_ALL_NEEDED;
+//  } else {  // data in current block is not earlier than current result
+//    return (pInfo->ts <= start) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
+//  }
 }
 
 static int32_t lastDistFuncRequired(SQLFunctionCtx *pCtx, TSKEY start, TSKEY end, int32_t colId) {
@@ -730,12 +733,16 @@ static int32_t lastDistFuncRequired(SQLFunctionCtx *pCtx, TSKEY start, TSKEY end
     return BLK_DATA_ALL_NEEDED;
   }
 
-  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
-  if (pInfo->hasResult != DATA_SET_FLAG) {
-    return BLK_DATA_ALL_NEEDED;
-  } else {
-    return (pInfo->ts > end) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
-  }
+  return BLK_DATA_ALL_NEEDED;
+  // TODO pCtx->aOutputBuf is the previous windowRes output buffer, not current unloaded block. so the following filter
+  // is invalid
+
+//  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
+//  if (pInfo->hasResult != DATA_SET_FLAG) {
+//    return BLK_DATA_ALL_NEEDED;
+//  } else {
+//    return (pInfo->ts > end) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
+//  }
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index b873714c493d1a3d0da3ab78a0e9ddfeb0ea6ad0..4bdebc8aeec2034f67362c2928272a877a322d79 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -784,6 +784,8 @@ static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed
   SQuery *        pQuery = pRuntimeEnv->pQuery;
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
+  bool hasPrev = pCtx[0].preAggVals.isSet;
+
   if (IS_MASTER_SCAN(pRuntimeEnv) || closed) {
     for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
       pCtx[k].nStartQueryTimestamp = pWin->skey;
@@ -796,11 +798,17 @@ static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed
       }
 
       // not a whole block involved in query processing, statistics data can not be used
-      pCtx[k].preAggVals.isSet = (forwardStep == numOfTotal);
+      // NOTE: the original value of isSet have been changed here
+      if (pCtx[k].preAggVals.isSet && forwardStep < numOfTotal) {
+        pCtx[k].preAggVals.isSet = false;
+      }
 
       if (functionNeedToExecute(pRuntimeEnv, &pCtx[k], functionId)) {
         aAggs[functionId].xFunction(&pCtx[k]);
       }
+
+      // restore it
+      pCtx[k].preAggVals.isSet = hasPrev;
     }
   }
 }
diff --git a/tests/script/general/parser/first_last_query.sim b/tests/script/general/parser/first_last_query.sim
index d11bdccb12066fb0d9249b3117f8b0dc00a5eca5..a4b891b54aefd49f07ba78a896b200897e4cefd4 100644
--- a/tests/script/general/parser/first_last_query.sim
+++ b/tests/script/general/parser/first_last_query.sim
@@ -65,22 +65,23 @@ endi
 if $data00 != @18-09-18 01:40:00.000@ then
   return -1   
 endi  
-#if $data01 != NULL then
+
 if $data01 != 999 then
   return -1   
-endi  
-#if $data02 != NULL then
+endi
+
 if $data02 != 999 then
   return -1  
-endi 
-#if $data03 != NULL then
+endi
+
 if $data03 != 999.00000 then
   return -1  
 endi    
-#if $data04 != NULL then
+
 if $data04 != 999.000000000 then
   return -1
 endi
+
 #if $data05 != NULL then
 if $data05 != 999 then
   return -1
@@ -127,7 +128,7 @@ if $data01 != 0 then
   return -1
 endi
 
-#add check for out of range first/last query
+print =============> add check for out of range first/last query
 sql select first(ts),last(ts) from first_tb4 where ts>'2018-9-18 1:40:01';
 if $row != 0 then
   return -1
@@ -136,4 +137,129 @@ endi
 sql select first(ts),last(ts) from first_tb4 where ts<'2018-9-17 8:50:0';
 if $row != 0 then
   return -1
+endi
+
+#first/last mix up query
+#select first(size),last(size) from stest interval(1d) group by tbname;
+print =====================>td-1477
+
+sql create table stest(ts timestamp,size INT,filenum INT) tags (appname binary(500),tenant binary(500));
+sql insert into test1 using stest tags('test1','aaa') values ('2020-09-04 16:53:54.003',210,3);
+sql insert into test2 using stest tags('test1','aaa') values ('2020-09-04 16:53:56.003',210,3);
+sql insert into test11 using stest tags('test11','bbb') values ('2020-09-04 16:53:57.003',210,3);
+sql insert into test12 using stest tags('test11','bbb') values ('2020-09-04 16:53:58.003',210,3);
+sql insert into test21 using stest tags('test21','ccc') values ('2020-09-04 16:53:59.003',210,3);
+sql insert into test22 using stest tags('test21','ccc') values ('2020-09-04 16:54:54.003',210,3);
+sql select sum(size) from stest group by appname;
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 420 then
+  return -1
+endi
+if $data10 != 420 then
+  return -1
+endi
+if $data20 != 420 then
+  return -1
+endi
+
+if $data01 != @test1@ then
+return -1
+endi
+if $data11 != @test11@ then
+return -1
+endi
+if $data21 != @test21@ then
+return -1
+endi
+
+sql select sum(size) from stest interval(1d) group by appname;
+if $rows != 3 then
+ return -1
+endi
+
+#2020-09-04 00:00:00.000 |                   420 | test1                          |
+#2020-09-04 00:00:00.000 |                   420 | test11                         |
+#2020-09-04 00:00:00.000 |                   420 | test21                         |
+if $data00 != @20-09-04 00:00:00.000@ then
+ return -1
+endi
+
+if $data10 != @20-09-04 00:00:00.000@ then
+ return -1
+endi
+
+if $data20 != @20-09-04 00:00:00.000@ then
+ return -1
+endi
+
+if $data01 != 420 then
+ print expect 420 , actual $data01
+ return -1
+endi
+
+if $data11 != 420 then
+ return -1
+endi
+
+if $data21 != 420 then
+ return -1
+endi
+
+if $data02 != @test1@ then
+return -1
+endi
+if $data12 != @test11@ then
+return -1
+endi
+if $data22 != @test21@ then
+return -1
+endi
+
+print ===================>td-1477, one table has only one block occurs this bug.
+sql select first(size),count(*),LAST(SIZE) from stest where tbname in ('test1', 'test2') interval(1d) group by tbname;
+if $rows != 2 then
+ return -1
+endi
+
+if $data00 != @20-09-04 00:00:00.000@ then
+  return -1
+endi
+
+if $data01 != 210 then
+  return -1
+endi
+
+if $data02 != 1 then
+  return -1
+endi
+
+if $data03 != 210 then
+ return -1
+endi
+
+if $data04 != @test1@ then
+  return -1
+endi
+
+if $data10 != @20-09-04 00:00:00.000@ then
+  return -1
+endi
+
+if $data11 != 210 then
+  return -1
+endi
+
+if $data12 != 1 then
+  return -1
+endi
+
+if $data13 != 210 then
+ return -1
+endi
+
+if $data14 != @test11@ then
+  return -1
 endi
\ No newline at end of file