Question

我有一个名为Business Entities“BE”的表和另一个名为Questionnaire“Q”的表，还有另一个名为“QBE”的表名称

表：BE

| BE_ID | Region | Name | Description | 
| 1     | A      | kl   | ssss        |
| 2     | A      | dds  | s saals     |
| 3     | B      | wf   | ksd ks skd  |
| 4     | B      | dsc  | sam sd  ;   |

表：Q

| Q_ID  | Name  | CreationDate  |
| 1     | sce   | 2014-01-01    |
| 2     | wcd   | 2014-02-01    |

表：QBE

| QBE_ID | BE_ID | Q_ID |
| 1      | 1     | 1    |
| 2      | 1     | 2    |
| 3      | 2     | 2    |

现在我想从 BE 中选择所有不同的区域，其中 Q 的CreationDate是最新的。

我正在研究这些问题。第一次加入

| QBE_ID | BE_ID | Q_ID | Region | Name | Name  | CreationDate  | 
| 1      | 1     | 1    | A      | kl   | sce   | 2014-01-01    |
| 2      | 1     | 2    | A      | dds  | sce   | 2014-02-01    |
| 3      | 2     | 2    | B      | wf   | wcd   | 2014-02-01    |

然后由此我想选择

| QBE_ID | BE_ID | Q_ID | Region | Name | Name  | CreationDate  | 
| 2      | 1     | 2    | A      | dds  | sce   | 2014-02-01    |
| 3      | 2     | 2    | B      | wf   | wcd   | 2014-02-01    |

对于所有区域“A”Q_ID“2”具有最新CreationDate的问卷，因此对于所有区域“B”，然后是所有其他区域。

到目前为止，这是我一直在做的事情，不要读它的复杂只是告诉我该怎么做。

SELECT BE.NAME00, QUES.ANSWER, QUES.DESCRIPTION, QT.CREATION_DATE
  FROM OPAGES.RV_ENTITY AS BE,
      OPAGES.RT__ENTITY_QUESTIONNAIRE AS EN_QT,
      OPAGES.RV_QUESTIONNAIRE AS QT,
      OPAGES.RT__QUESTIONNAIRE_QSECTION AS QT_SEC,
      OPAGES.RT__QSECTION_QUEST AS SEC_QUES, OPAGES.RT_QUEST AS QUES
  WHERE BE.ENTITY_ID = EN_QT.ENTITY_ID AND EN_QT.QUESTIONNAIRE_ID =
QT.QUESTIONNAIRE_ID
    AND QT.QUESTIONNAIRE_ID = QT_SEC.QUESTIONNAIRE_ID
    AND QT_SEC.QSECTION_ID = SEC_QUES.QSECTION_ID
    AND SEC_QUES.QUEST_ID = QUES.QUEST_ID
    AND QT.QUESTIONNAIRE_ID= (SELECT QT_SEC.QUESTIONNAIRE_ID
  FROM OPAGES.RT__QUESTIONNAIRE_QSECTION AS QT_SEC,
      OPAGES.RV_QUESTIONNAIRE AS QT
  WHERE QT.QUESTIONNAIRE_ID = QT_SEC.QUESTIONNAIRE_ID
  GROUP BY QT_SEC.QUESTIONNAIRE_ID, QT.CREATION_DATE
  ORDER BY QT.CREATION_DATE DESC
  FETCH FIRST ROW ONLY
)
  GROUP BY QT.CREATION_DATE, QUES.DESCRIPTION, QUES.ANSWER, BE.NAME00

我在想像

SELECT * 
FROM MyTable
WHERE (User, Date) IN
  ( SELECT User, MAX(Date) FROM MyTable GROUP BY User)

只是不能实现它

Answer 1

根据创建日期为每个BE_ID，Q_ID组合生成行号。外部选择为每个集合BE_ID，Q_ID采用最新值。

SELECT * from
(
    SELECT *, ROW_NUMBER() over ( partition by BE.BE_ID, Q.Q_ID order by Q.CreationDate desc) as seq
    FROM BE
    INNER JOIN QBE
    ON BE.BE_ID = QBE.QBE_ID
    INNER JOIN Q
    ON Q.Q_ID = QBE.Q_ID
) T
WHERE T.seq =1

Answer 2

完成，

SELECT *
FROM (
       SELECT 
       EN_QT.ENTITY_ID, 
       QT.QUESTIONNAIRE_ID, 
       QT.CREATION_DATE AS CREATION_DATE
       FROM 
       OPAGES.RV_QUESTIONNAIRE AS QT,
       OPAGES.RT__ENTITY_QUESTIONNAIRE AS EN_QT
       WHERE EN_QT.QUESTIONNAIRE_ID = QT.QUESTIONNAIRE_ID
       GROUP BY 
       EN_QT.ENTITY_ID, 
       QT.QUESTIONNAIRE_ID, 
       QT.CREATION_DATE
     )
       WHERE (ENTITY_ID, CREATION_DATE) 
       IN (
            SELECT 
            KILL.ENTITY_ID,
            MAX(KILL.CREATION_DATE)
            FROM (
                  SELECT 
                  EN_QT.ENTITY_ID,
                  QT.QUESTIONNAIRE_ID,
                  QT.CREATION_DATE AS CREATION_DATE
                  FROM 
                  OPAGES.RV_QUESTIONNAIRE AS QT,
                  OPAGES.RT__ENTITY_QUESTIONNAIRE AS EN_QT
                  WHERE 
                  EN_QT.QUESTIONNAIRE_ID =QT.QUESTIONNAIRE_ID

                  GROUP BY 
                  EN_QT.ENTITY_ID,
                  QT.QUESTIONNAIRE_ID,
                  QT.CREATION_DATE
                 ) AS KILL
                  GROUP BY KILL.ENTITY_ID
          )

复杂的JOIN查询，来自具有来自另一个TABLE的最新DATE属性的表的所有DISTINCT

2 个答案: