CASE语句或类似技术

Question

我想使用CASE语句，但没有得到我想要的答案。

下面是代码：

DECLARE @Table TABLE (DocID INT, DocNumber VARCHAR(10),DocDevStat INT, MilestoneDate DATETIME, 
         MilestoneID INT) 
INSERT INTO @Table VALUES (30, '14-1', 6, '10-01-2001', 10) 
INSERT INTO @Table VALUES (30, '14-1', 6, '10-15-2001', 11) 
INSERT INTO @Table VALUES (30, '14-1', 6, '11-06-2002', 13) 
INSERT INTO @Table VALUES (30, '14-1', 6, '11-01-2003', 27) 
INSERT INTO @Table VALUES (30, '14-1', 6, '11-01-2003', 30) 
INSERT INTO @Table VALUES (30, '14-1', 6, '03-01-2004', 28) 
INSERT INTO @Table VALUES (30, '14-1', 6, '03-01-2004', 35) 
INSERT INTO @Table VALUES (31, '14-3', 2, '06-27-2003', 10) 
INSERT INTO @Table VALUES (31, '14-3', 2, '05-05-2004', 27) 
INSERT INTO @Table VALUES (31, '14-3', 2, '05-05-2004', 30) 
INSERT INTO @Table VALUES (31, '14-3', 2, '07-20-2005', 35) 
INSERT INTO @Table VALUES (31, '14-3', 2, '08-31-2005', 32) 
INSERT INTO @Table VALUES (36, '1-2', 7, '10-01-1996', 10) 
INSERT INTO @Table VALUES (36, '1-2', 7, '10-01-1996', 11) 
INSERT INTO @Table VALUES (36, '1-2', 7, '12-01-1996', 28) 
INSERT INTO @Table VALUES (36, '1-2', 7, '12-01-1996', 35) 

Select distinct t.Docid, t.DocNumber, 

case when t.DocDevStat IN (6,7,8) and t.MilestoneID = 35 then Max(t.Milestonedate) 
    when t.DocDevStat IN (2,3,4) then Convert(date,GETDATE()) end AS LatestDate 

FROM @Table t 
Group By t.DocID, t.DocNumber, t.DocDevStat, t.MilestoneID 

结果我得到的是：

Docid  DocNumber LatestDate 
30   14-1   NULL 
30   14-1   2004-03-01 
31   14-3   2012-10-17 
36   1-2   NULL 
36   1-2   1996-12-01 

但我想获得：

Docid  DocNumber LatestDate 
30   14-1   2004-03-01 
31   14-3   2012-10-17 
36   1-2   1996-12-01 

是这样的说法对技术在这种情况下使用？

Answer 1

Select DISTINCT t.Docid, t.DocNumber, 
case when t.DocDevStat IN (6,7,8) then Max(t.Milestonedate) 
when t.DocDevStat IN (2,3,4) then Convert(date,GETDATE()) end AS LatestDate 
FROM @Table t 
where t.DocDevStat IN (2,3,4) OR (t.DocDevStat IN (6,7,8) and t.MilestoneID = 35) 
Group By t.DocID, t.DocNumber, t.DocDevStat, t.MilestoneID 

此查询返回您正在查找的数据。我将你正在搜索的条件添加到where子句中。