Oracle 查询难倒 - 派生 table

Question

我已经有很长时间没有完成最基本的 sql 查询了。但是我今天运行进入了这个，并花了几个小时在上面，并且坚持我的派生 table 尝试（这是针对 Oracle 数据库）。寻找一些提示。谢谢

TABLE: dtree
DataID  Name
-------------
10001   A.doc
10002   B.doc
10003   C.doc
10004   D.doc

TABLE: collections
CollectionID   DataID
---------------------
201     10001
201     10002   
202     10003
203     10004

TABLE: rimsNodeClassification
DataID  RimsSubject  RimsRSI  Status
---------------------------------------
10001   blah         IS-03  Active
10002   blah         LE-01  Active
10003   blah         AD-02  Active
10004   blah         AD-03  Active

TABLE:  rsiEventSched 
RimsRSI  RetStage  DateToUse  RetYears
--------------------------------------
IS-03   SEM-PHYS   95       1
IS-03   ACT       NULL      2
LE-01   SEM-PHYS   94       1
LE-01   INA-PHYS   95       2
LE-01   ACT       NULL      NULL
LE-01   OFC       NULL      NULL
LE-02   SEM-PHYS   94       2

正在尝试查询 CollectionID=201

INTENDED RESULT:
DataID  Name    RimsRSI  Status  SEMPHYS_DateToUse  INAPHYS_DateToUse      SEMPHYS_RetYears  INAPHYS_RetYears
-------------------------------------------------------------------------------------------------------
10001   A.doc   IS-03    Active   95               null                     1               null
10002   B.doc   Le-01    Active   94               95                   1                 2

Answer 1

您不需要 Derived Table，只需连接表（最后使用左连接）然后应用 MAX(CASE) 聚合：

select c.DataID, t.Name, rnc.RimsRSI, rnc.Status,
   max(case when res.RetStage = 'SEM-PHYS' then res.DateToUse end) SEMPHYS_DateToUse,
   max(case when res.RetStage = 'INA-PHYS' then res.DateToUse end) INAPHYS_DateToUse,
   max(case when res.RetStage = 'SEM-PHYS' then res.RetYears end) SEMPHYS_RetYears,
   max(case when res.RetStage = 'INA-PHYS' then res.RetYears end) INAPHYS_RetYears
from collections c
join dtree t
  on c.DataID = t.DataID
join rimsNodeClassification rnc
  on c.DataID = rnc.DataID
left join rsiEventSched res 
  on rnc.RimsRSI = res.RimsRSI
where c.CollectionID= 201
group by c.DataID, t.Name, rnc.RimsRSI, rnc.Status

Oracle 查询难倒 - 派生 table

Oracle query stumped - derived table

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