根據列的不同值查詢選擇行

Question

我當前的查詢有問題，我希望根據列獲取記錄/結果（示例列 Status 的值為 new/pending/completed 對於我執行的查詢，如果有 3 個狀態為 new 的記錄，它應該是過濾以僅顯示 1 條狀態為新的記錄）。 下面是我當前的查詢，它得到重復的列。

select a.CW_UPD_TMS,
          case when a.CW_CRT_UID='AAA' then 'BBB'
               else a.CW_CRT_UID end as CW_CRT_UID,  
          COALESCE(b.CW_S_BR, a.CW_S_BR) as CW_S_BR,
          a.CW_TRX_STAT as STATUS,   
          SUBSTR(a.CW_UPD_TMS,7,2) as day,
          SUBSTR(a.CW_UPD_TMS,5,2) as month,
          SUBSTR(a.CW_UPD_TMS,1,4) as ayear,   
          SUBSTR(a.CW_UPD_TMS,9,2) as hours,
          SUBSTR(a.CW_UPD_TMS,11,2) as mins,
          SUBSTR(a.CW_UPD_TMS,13,2) as secs,   
          case when cast(SUBSTR(a.CW_UPD_TMS,9,2) as INT) > 12 then 'PM'
               else 'AM' end as zone   
from  TABLEA  a  
    left outer join TABLEB b on a.CW_CRT_UID = b.CW_S_USR  
where a.CW_TRX_ID = '20150415110000798' 
union  
select a.CW_UPD_TMS,
          case when a.CW_CRT_UID='AAA' then 'BBB'
               else a.CW_CRT_UID end as CW_CRT_UID,  
          COALESCE(b.CW_S_BR, a.CW_S_BR) as CW_S_BR,
          a.CW_TRX_STAT as STATUS,   
          SUBSTR(a.CW_UPD_TMS,7,2) as day,
          SUBSTR(a.CW_UPD_TMS,5,2) as month,
          SUBSTR(a.CW_UPD_TMS,1,4) as ayear,   
          SUBSTR(a.CW_UPD_TMS,9,2) as hours,
          SUBSTR(a.CW_UPD_TMS,11,2) as mins,
          SUBSTR(a.CW_UPD_TMS,13,2) as secs,   
          case when cast(SUBSTR(a.CW_UPD_TMS,9,2) as INT) > 12 then 'PM'
               else 'AM' end as zone   
from  TABLEC  a  
    left outer join TABLEB b on a.CW_CRT_UID = b.CW_S_USR  
where a.CW_TRX_ID = '20150415110000798'

這是當前的結果：

CW_UPD_TMS          CW_CRT_UID  CW_S_BR STATUS  DAY MONTH   AYEAR   HOURS   MINS    SECS    ZONE
2015062610260746811 happy       KLC     NEW     26  06      2015    10      26      07      AM
2015062610273984711 happy       KLC     NEW     26  06      2015    10      27      39      AM
2015062610275762511 happy       KLC     NEW     26  06      2015    10      27      57      AM

那么現在如何更改查詢，以便僅顯示 1 條記錄（顯示 min(CW_UPD_TMS)），因為現在 3 條記錄具有相同的 STATUS (New) 。

我的預期結果應該是：

CW_UPD_TMS          CW_CRT_UID  CW_S_BR STATUS  DAY MONTH   AYEAR   HOURS   MINS    SECS    ZONE
2015062610260746811 happy       KLC     NEW     26  06      2015    10      26      07      AM

對不起我糟糕的英語。

Answer 1

它在您的情況下的預期行為。 除了“狀態”之外，您還應該想出另一列，以便它們可以形成復合鍵，這將是唯一的，並且您可以獲得單個記錄。

您可以有任何標准，如日期或任何符合您要求的標准，並使用行號屬性來限制結果為 1 條記錄。

讓我知道這是否有意義。

Answer 2

這可能是一個好的開始，但我不得不假設時間戳作為主鍵。 您應該在問題中提及您在哪個平台上。 如果我們了解 join 和 union 發生了什么，它也可能會更清晰。

select
    d.CW_UPD_TMS, CW_CRT_UID, CW_S_BR, STATUS, day, month, ayear, hours, mins, secs, zone   
from 
(
    select
        a.CW_UPD_TMS, case when a.CW_CRT_UID='AAA' then 'BBB' else a.CW_CRT_UID end as CW_CRT_UID,  
        case when b.CW_S_BR is null then a.CW_S_BR else b.CW_S_BR end as CW_S_BR, a.CW_TRX_STAT as STATUS,   
        SUBSTR(a.CW_UPD_TMS,7,2) as day, SUBSTR(a.CW_UPD_TMS,5,2) as month, SUBSTR(a.CW_UPD_TMS,1,4) as ayear,   
        SUBSTR(a.CW_UPD_TMS,9,2) as hours, SUBSTR(a.CW_UPD_TMS,11,2) as mins,SUBSTR(a.CW_UPD_TMS,13,2) as secs,   
        case when cast(SUBSTR(a.CW_UPD_TMS,9,2) as INT) > 12 then 'PM' else 'AM' end as zone   
    from TABLEA a left outer join TABLEB b on a.CW_CRT_UID = b.CW_S_USR  
    where a.CW_TRX_ID = '20150415110000798' 
    union  
    select
        a.CW_UPD_TMS, case when a.CW_CRT_UID='AAA' then 'BBB' else a.CW_CRT_UID end as CW_CRT_UID,  
        case when b.CW_S_BR is null then a.CW_S_BR else b.CW_S_BR end as CW_S_BR, a.CW_TRX_STAT as STATUS,   
        SUBSTR(a.CW_UPD_TMS,7,2) as day, SUBSTR(a.CW_UPD_TMS,5,2) as month, SUBSTR(a.CW_UPD_TMS,1,4) as ayear,   
        SUBSTR(a.CW_UPD_TMS,9,2) as hours, SUBSTR(a.CW_UPD_TMS,11,2) as mins,SUBSTR(a.CW_UPD_TMS,13,2) as secs,   
        case when cast(SUBSTR(a.CW_UPD_TMS,9,2) as INT) > 12 then 'PM' else 'AM' end as zone   
    from TABLEC a  
    left outer join TABLEB b on a.CW_CRT_UID = b.CW_S_USR  
    where a.CW_TRX_ID = '20150415110000798'
) as d /* data */ inner join
(
    select min(CW_UPD_TMS) as CW_UPD_TMS, CW_TRX_STAT
    from (
        select a.CW_UPD_TMS, a.CW_TRX_STAT
        from TABLEA a
        where a.CW_TRX_ID = '20150415110000798' 
        union  
        select c.CW_UPD_TMS, c.CW_TRX_STAT
        from TABLEC c
        where c.CW_TRX_ID = '20150415110000798'
    ) t0
    group by CW_TRX_STAT
) as r /* representative */
    on r.CW_UPD_TMS = d.CW_UPD_TMS and r.CW_TRX_STAT = d.CW_TRX_STAT

Answer 3

要獲取最舊的記錄，您需要按日期對記錄進行排名。 因此，您要做的是將 TableA 和 TableC 結合起來，給記錄一個數字，每個狀態中最舊的為 1，然后只保留這些記錄排名 1。

select a.cw_upd_tms,
  case when a.cw_crt_uid='AAA' then 'BBB'
       else a.cw_crt_uid end as cw_crt_uid,  
  coalesce(b.cw_s_br, a.cw_s_br) as cw_s_br,
  a.cw_trx_stat as status,   
  substr(a.cw_upd_tms,7,2) as day,
  substr(a.cw_upd_tms,5,2) as month,
  substr(a.cw_upd_tms,1,4) as ayear,   
  substr(a.cw_upd_tms,9,2) as hours,
  substr(a.cw_upd_tms,11,2) as mins,
  substr(a.cw_upd_tms,13,2) as secs,   
  case when cast(substr(a.cw_upd_tms,9,2) as int) > 12 then 'PM'
       else 'AM' end as zone   
from 
(
  select 
    cw_trx_stat, cw_crt_uid, cw_upd_tms
  from
  (
    select 
      cw_trx_stat, cw_crt_uid, cw_upd_tms,
      row_number() over (partition by cw_trx_stat order by cw_upd_tms) as rn
    from
    (
      select cw_trx_stat, cw_crt_uid, cw_upd_tms
      from tablea where cw_trx_id = '20150415110000798' 
      union all
      select cw_trx_stat, cw_crt_uid, cw_upd_tms
      from tablec where cw_trx_id = '20150415110000798' 
    ) combined
  ) ranked
  where rn = 1
) a
left outer join tableb b on a.cw_crt_uid = b.cw_s_usr;