Merge pull request #9215 from taosdata/fix/TD-12276

[TD-12276]<fix>: elapsed nest query: Return a negative calculation result

src/query/src/qAggMain.c

@@ -4870,7 +4870,8 @@ static void elapsedFinalizer(SQLFunctionCtx *pCtx) {
   }
 
   SElapsedInfo *pInfo = GET_ROWCELL_INTERBUF(GET_RES_INFO(pCtx));
-  *(double *)pCtx->pOutput = (double)pInfo->max - (double)pInfo->min;
+  double result = (double)pInfo->max - (double)pInfo->min;
+  *(double *)pCtx->pOutput = result >= 0 ? result : -result;
   if (pCtx->numOfParams > 0 && pCtx->param[0].i64 > 0) {
     *(double *)pCtx->pOutput = *(double *)pCtx->pOutput / pCtx->param[0].i64;
   }

tests/pytest/functions/function_elapsed_case.py

@@ -222,6 +222,13 @@ class ElapsedCase:
         self.orderbyForStableCheck("select elapsed(ts) from st1 where ts > '2021-11-22 00:00:00' and ts < '2021-11-23 00:00:00' interval(222m) group by tbname", 1, 2)
         self.orderbyForStableCheck("select elapsed(ts) from st1 where ts > '2021-11-22 00:00:00' and ts < '2021-11-23 00:00:00' interval(1000m) group by tbname", 1, 2)
 
+        #nested query
+        resAsc = tdSql.getResult("select elapsed(ts) from (select csum(i) from t1 where ts > '2021-11-22 00:00:00' and ts < '2021-11-23 00:00:00')")
+        resDesc = tdSql.getResult("select elapsed(ts) from (select csum(i) from t1 where ts > '2021-11-22 00:00:00' and ts < '2021-11-23 00:00:00' order by ts desc)")
+        resRows = len(resAsc)
+        for i in range(resRows):
+            tdSql.checkEqual(resAsc[i][0], resDesc[resRows - i - 1][0])
+
     def slimitCheck(self, sql):
         tdSql.checkEqual(tdSql.query(sql + " slimit 0"), 0)
         tdSql.checkEqual(tdSql.query(sql + " slimit 1 soffset 0"), tdSql.query(sql + " slimit 0, 1"))