與集合函數運行總和

Question

我正在檢索mlog表的結果，並在下面的代碼1的幫助下計算qtyn的小計。我一直堅持如何加入第一個代碼標準。

感謝您的幫助

1.

SELECT autn, date, itcode, qtyn, out, 
     date, phstock, 
     qtyn + COALESCE(
       (SELECT SUM(qtyn) FROM dbo.mlog b 
       WHERE b.autn < a.autn 
        AND itcode = '40'), 0) AS balance 
FROM dbo.mlog a 
WHERE (itcode = '40') 
ORDER BY autn 

2.

date >=(SELECT MAX([date]) FROM mlog) 

Answer 1

要追加一個狀態到代碼中，使用AND或OR。 EG：

SELECT a.autn, a.date, a.itcode, a.qtyn, a.out, 
     a.date, a.phstock, 
     a.qtyn + COALESCE(
       (SELECT SUM(b.qtyn) FROM dbo.mlog b 
       WHERE b.autn < a.autn 
        AND b.itcode = '40'), 0) AS balance 
FROM dbo.mlog a 
WHERE (a.itcode = '40' AND a.date >= (SELECT MAX([c.date]) FROM mlog c)) 
ORDER BY a.autn 

沒有測試，但應該做你想要

Answer 2

我聽說SQL Server是相當低效與coalesce()什麼，因爲它運行的第一部分的兩倍。下面是寫這個的另一種方式：

with ml as (
    SELECT ml.autn, ml.date, ml.itcode, ml.qtyn, ml.out, ml.date, ml.phstock 
    FROM dbo.mlog ml 
    WHERE ml.itcode = '40' AND ml.date >= (SELECT MAX(ml1.date]) FROM mlog ml1) 
    ) 
select ml.*, 
     (select sum(m1l.qtyn) from ml ml1 where ml1.autn <= ml.autn) as balance 
from ml 
ORDER BY ml.autn 

我也想知道，如果where條款是更有效，因爲：因爲周圍`日期所用的支架

WHERE ml.itcode = '40' AND ml.date = (SELECT top 1 ml1.date FROM mlog ml1 order by ml1.date desc)