SQL单一查询更新

Question

我不得不在我们的数据库中的新列中插入值，但我无法以一致的方式解决这个问题。有很多数据所以手动做任何事都是不可能的。让我上台：

我们有一个名为Occurrence的表和一个名为OccurenceBuckets的表，其中每个引用都引用已分配到的桶。以前这是一个单向引用，但由于各种原因，我们决定将OccurrenceBucket中的引用添加到第一个Occurrence（首先是时间，即）。表现在看起来像这样：

CREATE TABLE Occurrence
  OccurrenceID uniqueidentifier,
  OccurrenceBucketID uniqueidentifier,
  OccurrenceTime datetime,
  OccurrenceMessage nvarchar
  ...other meta data...

CREATE TABLE OccurrenceBucket
  OccurrenceBucketID uniqueidentifier,
  ...other meta data...
  FirstOccurrenceID uniqueidentifier,
  FirstOccurrenceTime datetime,
  FirstOccurrenceMessage nvarchar

我正在寻找一种方法来确定属于某个存储桶的第一个事件，并为FirstOccurrenceID，FirstOccurrenceTime和FirstOccurrenceMessage分配所有mybucket的第一次出现的值。

你们中的任何一位sql-fu专家都有时间帮助我，我所有的尝试都会产生不正确或不完整的事件选择。

Answer 1

你可以试试这个

DECLARE @Occurrence TABLE(
        OccurrenceID INT,
        OccurrenceBucketID INT,
        OccurrenceTime DATETIME,
        OccurrenceMessage VARCHAR(MAX)
)

INSERT INTO @Occurrence (OccurrenceID,OccurrenceBucketID,OccurrenceTime,OccurrenceMessage)  
SELECT 1, 1, '01 Jan 2009', 'A'
INSERT INTO @Occurrence (OccurrenceID,OccurrenceBucketID,OccurrenceTime,OccurrenceMessage)  
SELECT 2, 1, '02 Jan 2009', 'B'
INSERT INTO @Occurrence (OccurrenceID,OccurrenceBucketID,OccurrenceTime,OccurrenceMessage)  
SELECT 3, 1, '03 Jan 2009', 'C'


INSERT INTO @Occurrence (OccurrenceID,OccurrenceBucketID,OccurrenceTime,OccurrenceMessage)  
SELECT 4, 2, '04 Jan 2009', 'D'
INSERT INTO @Occurrence (OccurrenceID,OccurrenceBucketID,OccurrenceTime,OccurrenceMessage)  
SELECT 5, 2, '05 Jan 2009', 'E'
INSERT INTO @Occurrence (OccurrenceID,OccurrenceBucketID,OccurrenceTime,OccurrenceMessage)  
SELECT 6, 2, '06 Jan 2009', 'F'

SELECT * FROM @Occurrence

DECLARE @OccurrenceBucket TABLE(
        OccurrenceBucketID INT,
        FirstOccurrenceID INT,
        FirstOccurrenceTime DATETIME,
        FirstOccurrenceMessage VARCHAR(MAX)
)

INSERT INTO @OccurrenceBucket (OccurrenceBucketID) SELECT 1
INSERT INTO @OccurrenceBucket (OccurrenceBucketID) SELECT 2

SELECT * FROM @OccurrenceBucket


UPDATE  @OccurrenceBucket
SET     FirstOccurrenceID = OccurrenceID,
        FirstOccurrenceTime = OccurrenceTime,
        FirstOccurrenceMessage = OccurrenceMessage
FROM    @OccurrenceBucket oc INNER JOIN
        (
            SELECT  o.*
            FROM    @Occurrence o INNER JOIN
                    (
                        SELECT  OccurrenceBucketID,
                                MIN(OccurrenceID) FirstOccurrenceID
                        FROM    @Occurrence
                        GROUP BY OccurrenceBucketID
                    ) Mins ON o.OccurrenceID = mins.FirstOccurrenceID
        ) Vals ON oc.OccurrenceBucketID = Vals.OccurrenceBucketID

SELECT * FROM @OccurrenceBucket

编辑：

UPDATE  @OccurrenceBucket 
SET     FirstOccurrenceID = OccurrenceID, 
        FirstOccurrenceTime = OccurrenceTime, 
        FirstOccurrenceMessage = OccurrenceMessage 
FROM    @OccurrenceBucket oc INNER JOIN 
        ( 
                SELECT  o.* 
                FROM    @Occurrence o INNER JOIN 
                                ( 
                                        SELECT  OccurrenceBucketID, 
                                                        MIN(OccurrenceTime) FirstOccurrenceTime 
                                        FROM    @Occurrence 
                                        GROUP BY OccurrenceBucketID 
                                ) Mins ON o.OccurrenceTime = mins.FirstOccurrenceTime 
        ) Vals ON oc.OccurrenceBucketID = Vals.OccurrenceBucketID 

Answer 2

那么，要查找存储桶中的第一个事件，不应该进行以下工作吗？

SELECT TOP 1
  OccurranceID, OccurranceTime, OccurranceMessage
FROM Occurance
WHERE
  OccurranceBucketID = @OccurranceBucketID
ORDER BY
  OccurranceTime ASC

您可以将返回的字段分配给变量，然后相应地更新OccurranceBucket。

^{NB：“发生”没有“一个”在它。}

Answer 3

此答案依赖于OccurrenceTime对于每次出现都是唯一的： -

更新OccBuck设置
OccBuck.FirstOccurrenceID = Occ.OccurrenceID，
OccBuck.FirstOccurrenceTime = Occ.OccurrenceTime，
OccBuck.FirstOccurrenceMessage = Occ.OccurrenceMessage
从结果 dbo.OccurrenceBucket as OccBuck
内部联接dbo。在OccBuck.OccurrenceBucketID = Occ.OccurrenceBucketID上作为Occ发生 内连接（选择OccurrenceBucketID，
MIN（OccurrenceTime）为'MinOccurrenceTime'
来自dbo.Occurrence
Occ.OccurrenceBucketID = minOcc.OccurrenceBucketID和
作为minOcc on OccurrenceBucketID） Occ.OccurrenceTime = minOcc.MinOccurrenceTime