我有一个Documents表和一个Events表。
文档可能包含以下任何EventTypes的零个或多个事件：
DocID | EventType | EventDate | UserID
-----------------------------------------------
1 | 0 | 1-2-2017 | 123
1 | 1 | 1-3-2017 | 456
1 | 1 | 1-4-2017 | 489
1 | 2 | 1-5-2017 | 357
2 | 0 | 1-6-2017 | 951
2 | 1 | 1-7-2017 | 654
2 | 2 | 1-8-2017 | 654
2 | 3 | 1-9-2017 | 357
透过事件表很容易：
SELECT DocID, [0] AS CreatedDate, [1] AS ModifiedDate,
[2] AS SubmittedDate, [3] AS ApprovedDate
FROM (SELECT DocID, EventType, EventDate FROM Events
WHERE DocID IS NOT NULL AND EventDate IS NOT NULL) AS DocEvents
PIVOT (MAX(EventDate) FOR EventType IN ([0], [1], [2], [3]))
AS DocEventsPivot
出于我的目的，需要给定类型的最新事件，因此MAX聚合：
DocID | CreatedDate | ModifiedDate | SubmittedDate | ApprovedDate
-----------------------------------------------------------------
1 | 1-2-2017 | 1-4-2017 | 1-5-2017 | NULL
2 | 1-6-2017 | 1-7-2017 | 1-8-2017 | 1-9-2017
如何将UserID转换为CreatedBy，ModifiedBy，SubmittedBy和ApprovedBy以对应相应EventType的日期？
我不会提前知道UserID的可能值。
期望的输出：
DocID | CreatedDate | ModifiedDate | SubmittedDate | ApprovedDate | CreatedBy | ModifiedBy | SubmittedBy | ApprovedBy
---------------------------------------------------------------------------------------------------------------------
1 | 1-2-2017 | 1-4-2017 | 1-5-2017 | NULL | 123 | 489 | 357 | NULL
2 | 1-6-2017 | 1-7-2017 | 1-8-2017 | 1-9-2017 | 951 | 654 | 654 | 657
答案 0 :(得分：2)
而不是使用PIVOT，另一种解决方案是使用OUTER APPLY。
CREATE TABLE #Documents (ID int)
CREATE TABLE #Events (DocID int, EventType int, EventDate date, UserID int)
INSERT INTO #Documents VALUES
(1),
(2)
INSERT INTO #Events VALUES
(1, 0, '1-2-2017', 123),
(1, 1, '1-3-2017', 456),
(1, 1, '1-4-2017', 489),
(1, 2, '1-5-2017', 357),
(2, 0, '1-6-2017', 951),
(2, 1, '1-7-2017', 654),
(2, 2, '1-8-2017', 654),
(2, 3, '1-9-2017', 357)
SELECT
DOC.ID AS 'DocID',
CRT.EventDate AS 'CreatedDate',
MFY.EventDate AS 'ModifiedDate',
SUB.EventDate AS 'SubmittedDate',
APR.EventDate AS 'ApprovedDate',
CRT.UserID AS 'CreatedBy',
MFY.UserID AS 'ModifiedBy',
SUB.UserID AS 'SubmittedBy',
APR.UserID AS 'ApprovedBy'
FROM
#Documents AS DOC
OUTER APPLY (SELECT TOP 1 EventDate, UserID FROM #Events WHERE DocID = DOC.ID AND EventType = 0 ORDER BY EventDate DESC) AS CRT
OUTER APPLY (SELECT TOP 1 EventDate, UserID FROM #Events WHERE DocID = DOC.ID AND EventType = 1 ORDER BY EventDate DESC) AS MFY
OUTER APPLY (SELECT TOP 1 EventDate, UserID FROM #Events WHERE DocID = DOC.ID AND EventType = 2 ORDER BY EventDate DESC) AS SUB
OUTER APPLY (SELECT TOP 1 EventDate, UserID FROM #Events WHERE DocID = DOC.ID AND EventType = 3 ORDER BY EventDate DESC) AS APR
DROP TABLE #Documents
DROP TABLE #Events
答案 1 :(得分：1)
尝试以下
6或者您可以使用for (i = 0; i < data.length; i++) {
profileId = data[i][0];
clientCms = data[i][1];
goalList = data[i][3];
var goal1 = 'ga:goal' + goalList[0].toString() + 'Completions'
var goal2 = 'ga:goal' + goalList[1].toString() + 'Completions'
var goal3 = 'ga:goal' + goalList[2].toString() + 'Completions'
var goal4 = 'ga:goal' + goalList[3].toString() + 'Completions'
代替CREATE TABLE #Events (DocID int, EventType int, EventDate date, UserID int)
INSERT INTO #Events VALUES
(1, 0, '1-2-2017', 123),
(1, 1, '1-3-2017', 456),
(1, 1, '1-4-2017', 489),
(1, 2, '1-5-2017', 357),
(1, 2, '1-4-2017', 666),
(2, 0, '1-6-2017', 951),
(2, 1, '1-7-2017', 654),
(2, 2, '1-8-2017', 654),
(2, 3, '1-9-2017', 357)
SELECT
DocID,
MAX(CASE WHEN EventType=0 THEN EventDate END) [CreatedDate],
MAX(CASE WHEN EventType=1 THEN EventDate END) [ModifiedDate],
MAX(CASE WHEN EventType=2 THEN EventDate END) [SubmittedDate],
MAX(CASE WHEN EventType=3 THEN EventDate END) [ApprovedDate],
MAX(CASE WHEN EventType=0 THEN LastUserID END) [CreatedBy],
MAX(CASE WHEN EventType=1 THEN LastUserID END) [ModifiedBy],
MAX(CASE WHEN EventType=2 THEN LastUserID END) [SubmittedBy],
MAX(CASE WHEN EventType=3 THEN LastUserID END) [ApprovedBy]
FROM
(
SELECT
DocID,
EventDate,
EventType,
LAST_VALUE(UserID)OVER(
PARTITION BY DocID,EventType
ORDER BY EventDate
ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
) LastUserID
FROM #Events
) q
GROUP BY DocID
DROP TABLE #Events
。我更喜欢使用IFF，因为它不是阻止CASE
CASE