Question

我正在尝试使用之前的信息回填一列。像这样

BizID   Quarter Value
4168    201501  GOLD
4168    201502  NULL
4168    201503  NULL
4168    201504  NULL
4168    201601  REGISTERED
4168    201602  NULL
4168    201603  NULL
4168    201604  NULL

我想要什么

BizID   Quarter Value
4168    201501  GOLD
4168    201502  GOLD
4168    201503  GOLD
4168    201504  GOLD
4168    201601  REGISTERED
4168    201602  REGISTERED
4168    201603  REGISTERED
4168    201604  REGISTERED

我在Microsoft SQL Server 2014上运行。因此LAG（）函数不起作用，LAST_VALUE（）函数也不起作用。我尝试了这两个，导致相同的错误“Function（）不是公认的内置函数名称。”

我的完整代码如下。我创建了3个单独的表。第一个[DummyTable]只列出了8个季度。第二个[历史]引入PartnerAttributevalues（这些仅在发生更改时填充）。第三个[最新]从2014年之前的记录中搜索最相关信息并填写最高行值的信息。

SELECT DummyTable.BusinessID
    , DummyTable.Quarter
    , CASE WHEN ((History.PartnerAttributeValue IS NULL) AND (DummyTable.Quarter = 201501)) THEN Latest.PartnerAttributeValue
            ELSE History.PartnerAttributeValue
            END AS PartnerAttributeValue
            FROM 
                (SELECT BizID.BusinessID,Quart.Quarter
                    FROM(
                        (SELECT PPAV.BusinessID
                            FROM Partner_PartnerAttributeValue PPAV
                            WHERE PPAV.BusinessID = 4168
                            GROUP BY PPAV.BusinessID)BizID
                    CROSS JOIN 
                        (SELECT * FROM 
                        (VALUES ('201501', '2015-01-01','2015-03-31')
                              , ('201502', '2015-04-01','2015-06-30')
                              , ('201503', '2015-07-01','2015-09-30')
                              , ('201504', '2015-10-01','2015-12-31')
                              , ('201601', '2016-01-01','2016-03-31')
                              , ('201602', '2016-04-01','2016-06-30')
                              , ('201603', '2016-07-01','2016-09-31')
                              , ('201604', '2016-10-01','2016-12-31')) AS Quarters(Quarter,StartDate,EndDate)) Quart
                        )
                )DummyTable 
            LEFT JOIN
                (SELECT PPAV.BusinessID
                        , (cast(year(PPAV.PartnerAttributeValueStartDate) as char(4)) + '0' + cast(datepart(qq, PPAV.PartnerAttributeValueStartDate) as char(1))) AS Quarter
                        , PAV.PartnerAttributeValue
                    FROM Partner_PartnerAttributeValue PPAV
                    JOIN PartnerAttributeValue PAV
                        ON PAV.PartnerAttributeValueID = PPAV.PartnerAttributeValueID
                    WHERE PAV.PartnerAttributeID = 7
                        AND (PPAV.PartnerAttributeValueID = 22 OR PPAV.PartnerAttributeValueID = 795 OR PPAV.PartnerAttributeValueID = 796)
                        AND PPAV.BusinessID = 4168

                    GROUP BY PPAV.BusinessID
                            , (cast(year(PPAV.PartnerAttributeValueStartDate) as char(4)) + '0' + cast(datepart(qq, PPAV.PartnerAttributeValueStartDate) as char(1)))
                            , PAV.PartnerAttributeValue
                )History
                ON History.BusinessID = DummyTable.BusinessID
                AND History.Quarter = DummyTable.Quarter
            LEFT JOIN 
                (SELECT MAX(PPAV.PartnerAttributeValueStartDate) as MAXDate
                    , PAV.PartnerAttributeValue
                    , PPAV.BusinessID
                    FROM Partner_PartnerAttributeValue PPAV
                    JOIN PartnerAttributeValue PAV
                    ON PAV.PartnerAttributeValueID = PPAV.PartnerAttributeValueID
                    WHERE PAV.PartnerAttributeID = 7
                        AND (PPAV.PartnerAttributeValueID = 22 OR PPAV.PartnerAttributeValueID = 795 OR PPAV.PartnerAttributeValueID = 796)
                        AND (PPAV.BusinessID = 4168)
                        AND((cast(year(PPAV.PartnerAttributeValueStartDate) as char(4)) + '0' + cast(datepart(qq, PPAV.PartnerAttributeValueStartDate) as char(1))) < 201501)
                    GROUP BY PAV.PartnerAttributeValue
                        , PPAV.PartnerAttributeValueStartDate
                        , PPAV.BusinessID
                )Latest
            ON Latest.BusinessID = DummyTable.BusinessID

我正试图找出一种尽可能最有效地回填这些信息的方法。我提供的实例只查看了一个这样的实例。在更大的版本中，我将为成千上万的企业做这件事，因此效率是关键。

感谢您的帮助和指导！

Answer 1

SQL Server 2014支持

LAG()和LAST_VALUE()。您应该检查SQL Server兼容级别（请参阅here）。

在任何情况下，SQL Server都不支持IGNORE NULLS的{{1}}选项，这是最简单的方法。

这是另一种方式：

LAG()

如果您想要就地更改数据，这很容易合并到select t.BizID, t.Quarter, t.Value, tval.value as new_value from t outer apply (select top 1 t2.* from t2 where t2.BizID = t.BizId and t2.Value is not null and t2.Quarter <= t.Quarter order by t2.Quarter desc ) tval;中。

我正在尝试从该列

1 个答案: