Question

SQL到oracle的外部转换套用。

我有以下SQL查询：

    CREATE VIEW [dbo].[uvw_Templates_RecHist]
    AS
    SELECT RH.company_id
         , CI.company_name
         , RH.rec_date
         , RH.rec_code
         , RH.analyst_id
         , previous_rec_date = LRH.rec_date
         , previous_rec_code = LRH.rec_code
         , previous_analyst_id = LRH.analyst_id
         , [status] = CASE WHEN LRH.rec_date IS NULL THEN 'NEW'
                           WHEN RH.rec_code <> LRH.rec_code THEN 'CHANGE'
                           ELSE '' END
         , load_date = LoadDate
    FROM dbo.tblRecHist RH

    LEFT JOIN dbo.tblCompInd CI 
    ON RH.company_id = CI.company_id

    OUTER APPLY (
             SELECT A.company_id, A.rec_date, A.rec_code, A.analyst_id
             FROM dbo.tblRecHist A
             JOIN (
                   SELECT company_id, rec_date = MAX(rec_date) 
                   FROM dbo.tblRecHist WHERE rec_date < RH.rec_date
                   GROUP BY company_id
                   ) B
             ON A.company_id = B.company_id AND A.rec_date = B.rec_date
             WHERE A.company_id = RH.company_id
     ) LRH

    LEFT JOIN (
       SELECT LoadDate = MAX(LoadDate), AnalystID = MAX(AnalystName), 
              RecDate, CompanyID
       FROM dbo.tblTemplates_LoadLog 
       WHERE Loaded = 1
       GROUP BY RecDate, CompanyID
    )LL
    ON RH.company_id = LL.CompanyID AND RH.rec_date = LL.RecDate

我将其转换为以下oracle查询：

    CREATE VIEW uvw_Templates_RecHist
    AS
    SELECT RH.company_id
         , CI.company_name
         , RH.rec_date
         , RH.rec_code
         , RH.analyst_id
         , LRH.rec_date
         , LRH.rec_code
         , LRH.analyst_id
         , CASE WHEN LRH.rec_date IS NULL THEN 'NEW'
                WHEN RH.rec_code <> LRH.rec_code THEN 'CHANGE'
                ELSE '' END
         , LoadDate as load_date
    FROM tblRecHist RH

    LEFT JOIN tblCompInd CI 
    ON RH.company_id = CI.company_id

    LEFT OUTER JOIN (
          SELECT A.company_id, A.rec_date, A.rec_code, A.analyst_id
          FROM tblRecHist A
          JOIN (
            SELECT company_id, MAX(rec_date) 
            FROM tblRecHist WHERE rec_date < RH.rec_date
            GROUP BY company_id
            ) B
          ON A.company_id = B.company_id AND A.rec_date = B.rec_date
          WHERE A.company_id = RH.company_id
      ) LRH
     ON LRH.company_id=CI.company_id

    LEFT JOIN (
    SELECT MAX(LoadDate), MAX(AnalystName), RecDate, CompanyID
    FROM tblTemplates_LoadLog 
    WHERE Loaded = 1
    GROUP BY RecDate, CompanyID
    )LL
    ON RH.company_id = LL.CompanyID AND RH.rec_date = LL.RecDate

但是当我运行oracle查询时，出现以下错误：

ORA-00904：“ RH”。“ REC_DATE”：无效的标识符

1。即使没有编译时错误，为什么也会出现此错误。 2.如何解决？还有其他方法可以将查询从SQL转换为oracle。

Answer 1

在我看来，您的LRH子查询只是从tblRecHist获取上一行。这可能是使用LAG的地方，因为您要在同一张表中查找1行。

https://oracle-base.com/articles/misc/lag-lead-analytic-functions

假设company_id，rec_date是唯一的，则查询可能类似于以下内容。未测试，因为我没有您的数据库：

SELECT A.*
    ,CASE 
        WHEN previous_rec_date IS NULL
            THEN 'NEW'
        WHEN rec_code <> previous_rec_code
            THEN 'CHANGE'
        ELSE ''
        END
FROM (
    SELECT RH.company_id
        ,CI.company_name
        ,RH.rec_date
        ,RH.rec_code
        ,RH.analyst_id
        ,LAG(RH.rec_date) OVER (
            PARTITION BY RH.company_id ORDER BY rec_date
            ) AS previous_rec_date
        ,LAG(RH.rec_code) OVER (
            PARTITION BY RH.company_id ORDER BY rec_date
            ) AS previous_rec_code
        ,LAG(analyst_id) OVER (
            PARTITION BY RH.company_id ORDER BY rec_date
            ) AS previous_analyst_id
        ,LoadDate AS load_date
    FROM tblRecHist RH
    LEFT JOIN tblCompInd CI ON RH.company_id = CI.company_id
    LEFT JOIN (
        SELECT MAX(LoadDate) LoadDate
            ,MAX(AnalystName) AnalystName
            ,RecDate
            ,CompanyID
        FROM tblTemplates_LoadLog
        WHERE Loaded = 1
        GROUP BY RecDate
            ,CompanyID
        ) LL ON RH.company_id = LL.CompanyID
        AND RH.rec_date = LL.RecDate
    ) A

嵌套查询，以避免在出现“ NEW”和“ CHANGE”的情况下重复“ over（part by by。。。）”部分。

在Oracle中进行外部套用转换

1 个答案: