获取每个月最大日期的记录

Question

我想获取数据库中每年每年每个月的最高日期的余额。当客户进行交易时，余额表在每天结束时都有余额。 我只想在每个月的最高日期领取余额。有任何帮助吗？

下面是我的数据集的一部分。

Answer 1

您也可以执行此操作而无需子查询：

WITH b(ID, "date",bal) AS
  (
   SELECT 'CUST_I',DATE '2013-07-27', 14777.44 FROM dual UNION ALL
   SELECT 'CUST_H',DATE '2013-07-26', 71085.13 FROM dual UNION ALL
   SELECT 'CUST_I',DATE '2013-08-27', 66431.35656 FROM dual UNION ALL
   SELECT 'CUST_H',DATE '2013-08-26', 63102.68622 FROM dual UNION ALL
   SELECT 'CUST_H',DATE '2013-08-20', 6310.68622 FROM dual UNION ALL
   SELECT 'CUST_H',DATE '2013-08-10', 630.68622 FROM dual UNION ALL
   SELECT 'CUST_G',DATE '2013-09-25', 89732.04889 FROM dual UNION ALL
   SELECT 'CUST_E',DATE '2013-09-23', 83074.70822 FROM dual 
  )
SELECT ID,  
    MAX("date") KEEP (DENSE_RANK FIRST ORDER BY "date" desc) AS MAX_DATE,
    MAX(bal) KEEP (DENSE_RANK FIRST ORDER BY "date" desc) AS MAX_BAL
FROM b
GROUP BY ID, TRUNC("date", 'MM');

+-----------------------------+
|ID    |MAX_DATE  |MAX_BAL    |
+-----------------------------+
|CUST_E|23.09.2013|83074.70822|
|CUST_G|25.09.2013|89732.04889|
|CUST_H|26.07.2013|71085.13   |
|CUST_H|26.08.2013|63102.68622|
|CUST_I|27.07.2013|14777.44   |
|CUST_I|27.08.2013|66431.35656|
+-----------------------------+

Answer 2

您可以加入分组数据：

SELECT *
FROM t
INNER JOIN (
    SELECT ID, MAX(Date) AS Date_Last
    FROM t
    GROUP BY ID, EXTRACT(YEAR FROM Date), EXTRACT(MONTH FROM Date)
) AS x ON t.ID = x.ID AND t.Date = x.Date_Last

Answer 3

您可以尝试使用窗口函数-row_number（）

select * from
(
SELECT *,row_number() over(partition by extract(YEAR FROM Date), extract(MONTH FROM Date) order by date desc) as rn
FROM t
)rn=1

Answer 4

您可以对表调用cust_balances使用自联接：

select c1.*
  from cust_balances c1
join 
(  
  select max("date") max_date
    from cust_balances
   group by to_char("date",'yyyymm')  
) c2 on ( c1."date" = c2.max_date );

SQL Fiddle Demo