SELECT U1 AS Участник1, U2 AS Участник2, Sum(U2In) AS [Получил от Участника1], Sum(U2Out) AS [Отдал Участнику1], Sum(U2In)-Sum(U2Out) AS [Должен Участнику1]
FROM [SELECT SubMemo.ID_memo, Memo.uchastnik AS U1, SubMemo.uchastnik AS U2, SubMemo.poluchil AS U2In, SubMemo.otdal AS U2Out
FROM [Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo
UNION ALL
SELECT SubMemo.ID_memo, SubMemo.uchastnik AS U1, Memo.uchastnik AS U2, SubMemo.otdal AS U2In, SubMemo.poluchil AS U2Out
FROM [Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo]. AS [%$##@_Alias]
GROUP BY U1, U2;

SELECT U1 AS Участник1, U2 AS Участник2, Sum(U2In) AS [Получил от Участника1], Sum(U2Out) AS [Отдал Участнику1], Sum(U2In)-Sum(U2Out) AS [Должен Участнику1]
FROM (SELECT SubMemo.ID_memo, Memo.uchastnik AS U1, SubMemo.uchastnik AS U2, SubMemo.poluchil AS U2In, SubMemo.otdal AS U2Out
FROM [Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo
UNION ALL
SELECT SubMemo.ID_memo, SubMemo.uchastnik AS U1, Memo.uchastnik AS U2, SubMemo.otdal AS U2In, SubMemo.poluchil AS U2Out
FROM [Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo) AS Q
GROUP BY U1, U2;

SELECT U1 AS Участник1, U2 AS Участник2, Sum(U2In) AS [Получил от Участника1], Sum(U2Out) AS [Отдал Участнику1], Sum(U2In)-Sum(U2Out) AS [Должен Участнику1]
FROM (SELECT SubMemo.ID_memo, Memo.uchastnik AS U1, SubMemo.uchastnik AS U2, SubMemo.poluchil AS U2In, SubMemo.otdal AS U2Out
FROM [Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo
WHERE dataP<#02/02/2017#
UNION ALL
SELECT SubMemo.ID_memo, SubMemo.uchastnik AS U1, Memo.uchastnik AS U2, SubMemo.otdal AS U2In, SubMemo.poluchil AS U2Out
FROM [Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo
WHERE dataP<#02/02/2017#) AS Q
GROUP BY U1, U2;

SELECT U1 AS Участник1, U2 AS Участник2, Sum(U2In) AS [Получил от Участника1], Sum(U2Out) AS [Отдал Участнику1], Sum(U2In)-Sum(U2Out) AS [Должен Участнику1]
FROM [SELECT SubMemo.ID_memo, Memo.uchastnik AS U1, SubMemo.uchastnik AS U2, SubMemo.poluchil AS U2In, SubMemo.otdal AS U2Out
FROM (Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo
WHERE dataP>=#02/02/2017#
UNION ALL
SELECT SubMemo.ID_memo, SubMemo.uchastnik AS U1, Memo.uchastnik AS U2, SubMemo.otdal AS U2In, SubMemo.poluchil AS U2Out
FROM [Memo] INNER JOIN SubMemo ON Memo.ID_memo = SubMemo.ID_memo
WHERE dataP>=#02/02/2017#) AS Q
GROUP BY U1, U2;

SELECT *, Запрос2.Участник1 AS U1, Запрос2.Участник2 AS U2, Запрос2.[Должен Участнику1]+0 AS Итого
FROM Запрос2 LEFT JOIN Запрос3 ON (Запрос2.Участник1 = Запрос3.Участник1) AND (Запрос2.Участник2 = Запрос3.Участник2)
WHERE Запрос3.Участник1 Is Null AND Запрос3.Участник2 Is Null
UNION ALL
SELECT *, Запрос3.Участник1 AS U1, Запрос3.Участник2 AS U2, Запрос3.[Должен Участнику1]+0 AS Итого
FROM Запрос2 RIGHT JOIN Запрос3 ON (Запрос2.Участник1 = Запрос3.Участник1) AND (Запрос2.Участник2 = Запрос3.Участник2)
WHERE Запрос2.Участник1 Is Null AND Запрос2.Участник2 Is Null
UNION ALL 
SELECT *, Запрос2.Участник1 AS U1, Запрос2.Участник2 AS U2, Запрос2.[Должен Участнику1]+Запрос3.[Должен Участнику1] AS Итого
FROM Запрос2 INNER JOIN Запрос3 ON (Запрос2.Участник1 = Запрос3.Участник1) AND (Запрос2.Участник2 = Запрос3.Участник2);