From 998c5f18421a2cb5fd31c3b7e1187c438864fb56 Mon Sep 17 00:00:00 2001
From: shenglian zhou <shenglian_zhou@163.com>
Date: Sat, 19 Jun 2021 16:09:41 +0800
Subject: [PATCH] [TD-4735]<feature>:support select last_row from subquery

---
 src/client/src/tscSQLParser.c           | 11 +++++++++--
 tests/script/general/parser/lastrow.sim | 15 ++++++++++++++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 9532d1e202..d7fbdd3ff8 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -2125,7 +2125,10 @@ void setResultColName(char* name, tSqlExprItem* pItem, int32_t functionId, SStrT
 }
 
 static void updateLastScanOrderIfNeeded(SQueryInfo* pQueryInfo) {
-  if (pQueryInfo->sessionWindow.gap > 0 || tscGroupbyColumn(pQueryInfo)) {
+  if (pQueryInfo->sessionWindow.gap > 0 ||
+      pQueryInfo->stateWindow ||
+      taosArrayGetSize(pQueryInfo->pUpstream) > 0 ||
+      tscGroupbyColumn(pQueryInfo)) {
     size_t numOfExpr = tscNumOfExprs(pQueryInfo);
     for (int32_t i = 0; i < numOfExpr; ++i) {
       SExprInfo* pExpr = tscExprGet(pQueryInfo, i);
@@ -2385,7 +2388,9 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
       // NOTE: has time range condition or normal column filter condition, the last_row query will be transferred to last query
       SConvertFunc cvtFunc = {.originFuncId = functionId, .execFuncId = functionId};
-      if (functionId == TSDB_FUNC_LAST_ROW && ((!TSWINDOW_IS_EQUAL(pQueryInfo->window, TSWINDOW_INITIALIZER)) || (hasNormalColumnFilter(pQueryInfo)))) {
+      if (functionId == TSDB_FUNC_LAST_ROW && ((!TSWINDOW_IS_EQUAL(pQueryInfo->window, TSWINDOW_INITIALIZER)) ||
+                                               (hasNormalColumnFilter(pQueryInfo)) ||
+                                               taosArrayGetSize(pQueryInfo->pUpstream)>0)) {
         cvtFunc.execFuncId = TSDB_FUNC_LAST;
       }
 
@@ -7836,6 +7841,8 @@ int32_t validateSqlNode(SSqlObj* pSql, SSqlNode* pSqlNode, SQueryInfo* pQueryInf
     if ((code = doFunctionsCompatibleCheck(pCmd, pQueryInfo, tscGetErrorMsgPayload(pCmd))) != TSDB_CODE_SUCCESS) {
       return code;
     }
+
+    updateLastScanOrderIfNeeded(pQueryInfo);
   } else {
     pQueryInfo->command = TSDB_SQL_SELECT;
 
diff --git a/tests/script/general/parser/lastrow.sim b/tests/script/general/parser/lastrow.sim
index 2b8f294d5d..fea322ec16 100644
--- a/tests/script/general/parser/lastrow.sim
+++ b/tests/script/general/parser/lastrow.sim
@@ -70,4 +70,17 @@ sleep 100
 
 run general/parser/lastrow_query.sim
 
-system sh/exec.sh -n dnode1 -s stop -x SIGINT
\ No newline at end of file
+print =================== last_row + nested query
+sql use $db
+sql create table lr_nested(ts timestamp, f int)
+sql insert into lr_nested values(now, 1)
+sql insert into lr_nested values(now+1s, null)
+sql select last_row(*) from (select * from lr_nested)
+if $rows != 1 then
+  return -1
+endi
+if $data01 != NULL then
+  return -1
+endi
+
+system sh/exec.sh -n dnode1 -s stop -x SIGINT