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sql - Oracle 查询未返回来自两个子查询的所有行

问题描述

我有两个子查询，它们本质上是在查询相同的东西减去一个维度（标志列）。然后我从这两个子查询中获取数据并在“外部查询”中返回它们。（原始值和 RE 值 (VAL) 在同一行中）

我加入的复合键由以下列组成：

P_NAME, REAL_DATE, UTC_TIME, DATA_TYPE & LOCAL_TS

从第一个子查询返回的一些示例数据

P_NAME    REAL_DATE   UTC_TIME    DATA_TYPE   VAL   LOCAL_TS      FLAG
John      01-01-2018  01:00:00AM  Height      60    04:00:00AM    ORIG
Jacob     01-01-2018  02:00:00AM  Height      68    05:00:00AM    ORIG
Jingle    01-01-2018  01:00:00AM  Height      65    04:00:00AM    ORIG
Heimer    01-01-2018  04:00:00AM  Height      68    07:00:00AM    ORIG
Schmidt   01-01-2018  05:00:00AM  Height      72    08:00:00AM    ORIG

从第二个子查询返回的一些示例数据

P_NAME    REAL_DATE   UTC_TIME    DATA_TYPE   VAL   LOCAL_TS      FLAG
John      01-01-2018  01:00:00AM  Height      90    04:00:00AM    RE
Jacob     01-01-2018  02:00:00AM  Height      98    05:00:00AM    RE
Jingle    01-01-2018  01:00:00AM  Height      95    04:00:00AM    RE

我需要从第一个和第二个子查询返回

P_NAME    REAL_DATE   UTC_TIME    DATA_TYPE   O_VAL  RE_VAL    LOCAL_TS
John      01-01-2018  01:00:00AM  Height      60       90      04:00:00AM
Jacob     01-01-2018  02:00:00AM  Height      68       98      05:00:00AM
Jingle    01-01-2018  01:00:00AM  Height      65       95      04:00:00AM
Heimer    01-01-2018  04:00:00AM  Height      68      null     07:00:00AM
Schmidt   01-01-2018  05:00:00AM  Height      72      null     08:00:00AM

我尝试过但不起作用的方法：

select O.O_P_NAME as P_NAME
     , O.O_REAL_DATE as REAL_DATE
     , O.O_UTC_TIME as UTC_TIME
     , O.O_DATA_TYPE as DATA_TYPE
     , CASE WHEN O.O_VAL = R.R_VAL
            THEN null
            ELSE R.R_VAL
             END     as RESUBMITTED_VAL
     , O.O_VAL       as ORIG_VAL
     , O.O_LOCAL_TS  as LOCAL_TS
    FROM(
        (SELECT P_NAME as O_P_NAME
              , REAL_DATE as O_REAL_DATE
              , UTC_TIME as O_UTC_TIME
              , DATA_TYPE as O_DATA_TYPE
              , VAL as O_VAL
              , LOCAL_TS as O_LOCAL_TS
              , FLAG as O_FLAG
           FROM TABLE
          WHERE FLAG = 'ORIG' 
        ) O
        JOIN
        (SELECT P_NAME as R_P_NAME
              , REAL_DATE as R_REAL_DATE
              , UTC_TIME as R_UTC_TIME
              , DATA_TYPE as R_DATA_TYPE
              , VAL as R_VAL
              , LOCAL_TS as R_LOCAL_TS
              , FLAG as R_FLAG
           FROM TABLE
          WHERE FLAG = 'RE' 
        ) R
        ON O.O_P_NAME = R.R_P_NAME
       AND O.O_REAL_DATE = R.R_REAL_DATE
       AND O.O_UTC_TIME = R.R_UTC_TIME
       AND O.O_DATA_TYPE = R.R_DATA_TYPE
       AND O.O_LOCAL_TS = R.R_LOCAL_TS
        );

标签： sqloracle

解决方案

您不需要这两个子查询。只需做一个 case 语句来分隔字段。

SELECT P_NAME 
              , REAL_DATE 
              , UTC_TIME 
              , DATA_TYPE 
              , MAX(CASE WHEN FLAG='ORIG' THEN VAL END) as O_VAL
              , MAX(CASE WHEN FLAG='RE' THEN VAL END) as R_VAL
              , LOCAL_TS 
           FROM TABLE
GROUP BY P_NAME, REAL_DATE, UTC_TIME, DATA_TYPE, LOCAL_TS

奖励答案：如果您真的决定需要子查询，请使用 UNION 而不是连接，因为您不知道哪个表会有额外的值。

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