Question

我已经尝试找出每个客户12个月的每月总销售额，总寄回值。

使用其他2个子查询，然后查询变为每行使用26个子查询，而sql语句非常大。

然后我创建了两个subselect for sale和sendback totals ...

结果查询变短但执行时间大于20-30次。

这是正常的
如果subqery返回NULL，我怎么能返回0 ..

编辑：

(Select sum(chh2.cha_meblag)
 from dbo.CARI_HESAP_HAREKETLERI chh2
 where chh2.cha_normal_Iade=1 and
       chh2.cha_kod=ch.cari_kod and
       (chh2.cha_tarihi>='20130101' and chh2.cha_tarihi<='20130131')
) as Ocai

Answer 1

第二个问题的答案是将子查询包装在coalesce()：

中

coalesce((Select sum(chh2.cha_meblag)
          from dbo.CARI_HESAP_HAREKETLERI chh2
          where chh2.cha_normal_Iade=1 and
                chh2.cha_kod=ch.cari_kod and
                (chh2.cha_tarihi>='20130101' and chh2.cha_tarihi<='20130131')
         ), '') as Ocai

正如Martin在评论中指出的那样，coalesce()具有我认为是SQL Server中的错误。在这种情况下，它将执行两次第一个表达式，一次检查NULL的值，第二次执行值。鉴于此，ISNULL()更好（即使我更喜欢标准函数）：

isnull((Select sum(chh2.cha_meblag)
          from dbo.CARI_HESAP_HAREKETLERI chh2
          where chh2.cha_normal_Iade=1 and
                chh2.cha_kod=ch.cari_kod and
                (chh2.cha_tarihi>='20130101' and chh2.cha_tarihi<='20130131')
         ), '') as Ocai

Answer 2

根据您的子查询，您可以在没有相关子查询的情况下解决您的问题，并且只使用联接。但是，只有一部分查询可以使用它很难确定。这就是为什么在发布问题时，尽可能多地发布相关代码是个好主意。尽管如此，从我收集的内容来看，你有这样的事情：

SELECT  (   SELECT  SUM(chh2.cha_meblag)
            FROM    dbo.CARI_HESAP_HAREKETLERI chh2
            WHERE   chh2.cha_normal_Iade = 1 
            AND     chh2.cha_kod = ch.cari_kod
            AND     chh2.cha_tarihi >= '20130101' 
            AND     chh2.cha_tarihi <= '20130131'
        ) AS Ocai,
        (   SELECT  SUM(chh2.cha_meblag)
            FROM    dbo.CARI_HESAP_HAREKETLERI chh2
            WHERE   chh2.cha_normal_Iade = 1 
            AND     chh2.cha_kod = ch.cari_kod
            AND     chh2.cha_tarihi >= '20130201' 
            AND     chh2.cha_tarihi <= '20130228'
        ) AS Ocai,
        ... etc for 12 months
FROM    SomeTable ch

你可以把它变成：

SELECT  ch.cari_kod,
        [20130101] = ISNULL([20130101], 0),
        [20130201] = ISNULL([20130201], 0),
        [20130301] = ISNULL([20130301], 0),
        [20130401] = ISNULL([20130401], 0),
        [20130501] = ISNULL([20130501], 0),
        [20130601] = ISNULL([20130601], 0),
        [20130701] = ISNULL([20130701], 0),
        [20130801] = ISNULL([20130801], 0),
        [20130901] = ISNULL([20130901], 0),
        [20131001] = ISNULL([20131001], 0),
        [20131101] = ISNULL([20131101], 0),
        [20131201] = ISNULL([20131201], 0)
FROM    SomeTable
        LEFT JOIN
        (   SELECT  chh2.cha_kod,
                    [20130101] = SUM(CASE WHEN chh2.cha_tarihi >= '20130101' AND chh2.cha_tarihi < '20130201' THEN chh2.cha_meblag ELSE 0 END),
                    [20130201] = SUM(CASE WHEN chh2.cha_tarihi >= '20130201' AND chh2.cha_tarihi < '20130301' THEN chh2.cha_meblag ELSE 0 END),
                    [20130301] = SUM(CASE WHEN chh2.cha_tarihi >= '20130301' AND chh2.cha_tarihi < '20130401' THEN chh2.cha_meblag ELSE 0 END),
                    [20130401] = SUM(CASE WHEN chh2.cha_tarihi >= '20130401' AND chh2.cha_tarihi < '20130501' THEN chh2.cha_meblag ELSE 0 END),
                    [20130501] = SUM(CASE WHEN chh2.cha_tarihi >= '20130501' AND chh2.cha_tarihi < '20130601' THEN chh2.cha_meblag ELSE 0 END),
                    [20130601] = SUM(CASE WHEN chh2.cha_tarihi >= '20130601' AND chh2.cha_tarihi < '20130701' THEN chh2.cha_meblag ELSE 0 END),
                    [20130701] = SUM(CASE WHEN chh2.cha_tarihi >= '20130701' AND chh2.cha_tarihi < '20130801' THEN chh2.cha_meblag ELSE 0 END),
                    [20130801] = SUM(CASE WHEN chh2.cha_tarihi >= '20130801' AND chh2.cha_tarihi < '20130901' THEN chh2.cha_meblag ELSE 0 END),
                    [20130901] = SUM(CASE WHEN chh2.cha_tarihi >= '20130901' AND chh2.cha_tarihi < '20131001' THEN chh2.cha_meblag ELSE 0 END),
                    [20131001] = SUM(CASE WHEN chh2.cha_tarihi >= '20131001' AND chh2.cha_tarihi < '20131101' THEN chh2.cha_meblag ELSE 0 END),
                    [20131101] = SUM(CASE WHEN chh2.cha_tarihi >= '20131101' AND chh2.cha_tarihi < '20131201' THEN chh2.cha_meblag ELSE 0 END),
                    [20131201] = SUM(CASE WHEN chh2.cha_tarihi >= '20131201' AND chh2.cha_tarihi < '20140101' THEN chh2.cha_meblag ELSE 0 END)
            FROM    dbo.CARI_HESAP_HAREKETLERI chh2
            WHERE   chh2.cha_normal_Iade = 1 
            GROUP BY chh2.cha_kod
        ) chh2
            ON chh2.cha_kod = ch.cari_kod;

这甚至可能不需要子查询，但正如我所说，如果没有完整的查询，我只能推测你的表格结构，以及你真正想要的结果。

要回答1是，UDF执行比执行相同操作的子查询更糟糕是正常的。当我搜索This answer

时，主题上有很多帖子SQL-Server UDF versus subquery是google的顶部

UDF与子查询性能问题

2 个答案: