SELECT
    t.tw_Symbol AS [Symbol],
    t.tw_Nazwa AS [Nazwa],

    CAST(SUM(ISNULL(s.st_Stan, 0)) AS decimal(18,3)) AS [Stan],

    CAST(
        SUM(ISNULL(s.st_Stan, 0))
        - SUM(ISNULL(s.st_StanRez, 0))
        AS decimal(18,3)
    ) AS [Dostępne],

    t.tw_JednMiary AS [Jednostka miary]

FROM [subiekt_GT_nazwa_bazy].dbo.tw__Towar t

LEFT JOIN [subiekt_GT_nazwa_bazy].dbo.tw_Stan s
    ON s.st_TowId = t.tw_Id

WHERE NOT EXISTS
(
    SELECT 1
    FROM [sello_nx_nazwa_bazy].ModelDanychContainer.OfertyInternetowe oi
    LEFT JOIN [sello_nx_nazwa_bazy].ModelDanychContainer.Asortymenty a
        ON a.Id = oi.Asortyment_Id
    WHERE oi.Status = 61
      AND a.Symbol = t.tw_Symbol
)

GROUP BY
    t.tw_Id,
    t.tw_Symbol,
    t.tw_Nazwa,
    t.tw_JednMiary

HAVING
    SUM(ISNULL(s.st_Stan, 0)) - SUM(ISNULL(s.st_StanRez, 0)) > 0

ORDER BY
    t.tw_Symbol