Oracle-按日期分組

Question

我在Oracle 11g數據庫中有一個這樣的表

TABLE REC
REC_ID NUMBER
CARD_ID NUMBER
REC_STATUS NUMBER
REC_DATE TIMESTAMP

我想知道在給定期間內已充值多少張卡，但是我希望此信息按日期分組。 如果card_id已在某一日期計算，則不應在下一個日期計算（區別）。

這里一些測試數據

with
     REC ( REC_ID, CARD_ID, REC_STATUS, REC_DATE ) as (
       select '1', '100', '1', SYSTIMESTAMP - 5 from dual union all
       select '2', '100', '1', SYSTIMESTAMP - 5  from dual union all
       select '3', '200', '1', SYSTIMESTAMP - 5  from dual union all
       select '4', '100', '1', SYSTIMESTAMP - 4  from dual union all
       select '5', '300', '1', SYSTIMESTAMP - 4  from dual union all
       select '6', '200', '1', SYSTIMESTAMP - 4  from dual union all
       select '7', '100', '1', SYSTIMESTAMP - 3  from dual union all
       select '8', '400', '1', SYSTIMESTAMP - 3  from dual union all
       select '9', '400', '1', SYSTIMESTAMP - 3  from dual union all
       select '10', '400', '1', SYSTIMESTAMP - 2  from dual union all
       select '11', '300', '1', SYSTIMESTAMP - 2  from dual union all
       select '12', '100', '1', SYSTIMESTAMP - 2  from dual union all
       select '13', '400', '1', SYSTIMESTAMP - 2  from dual 
     )
-- end of test data

當我執行這樣的查詢時，我的總數為4，這是正確的。

SELECT  
    COUNT(DISTINCT CARD_ID) COUNT 
FROM REC 
WHERE REC_STATUS = 1

結果

|COUNT|
|   4 |

但是，當我嘗試這種方式時，我的總數為10。這是因為當我在日期上使用“ group by”並在ID中使用“ distinct”時，區別僅適用於分組日期，不是整個時期。

SELECT  
    TRUNC(REC_DATE) DAT, 
    COUNT(DISTINCT CARD_ID) COUNT
FROM REC 
WHERE REC_STATUS = 1
GROUP BY TRUNC(REC_DATE)

結果

DAT      | COUNT
14/06/19 |   2
13/06/19 |   3
15/06/19 |   3
12/06/19 |   2

我該怎么做才能將差異應用於期間總計，並且仍按日期保留分組？

Answer 1

也許您只想要每張卡的最早日期：

SELECT TRUNC(MIN_REC_DATE) as DAT, 
        COUNT(*) as COUNT
FROM (SELECT CARD_ID, MIN(REC_DATE) as MIN_REC_DATE
      FROM REC
      WHERE REC_STATUS = 1 
      GROUP BY CARD_ID
     ) R
GROUP BY TRUNC(MIN_REC_DATE);