Question

需要更新表中的值。本质上，我已经添加了fromDate和toDate列。我在thepriceDate上设置的值：

UPDATE schema.myTable SET FROMDATE = PRICEDATE, TODATE = PRICEDATE WHERE FROMDATE IS NULL AND TODATE IS NULL

这有效。然后，我需要将最新日期设置为6000-01-01。所有行都是唯一的，但可以与相似的对象相关。所以我可能有：

priceDate | fromDate | toDate | INSTRUMENT | uniqueID 25/09/2018 25/09/2018 25/09/2018 AUD | 1 26/09/2018 26/09/2018 26/09/2018 EUR | 2 25/09/2018 25/09/2018 25/09/2018 EUR | 3 25/09/2018 25/09/2018 25/09/2018 JPN | 4 29/09/2018 29/09/2018 29/09/2018 EUR | 5 29/09/2018 29/09/2018 29/09/2018 JPN | 6 20/09/2018 20/09/2018 20/09/2018 JPN | 7 28/09/2018 28/09/2018 28/09/2018 AUD | 8

我尝试过： UPDATE schema.myTable SET TODATE = TO_DATE('60000101', 'yyyymmdd') WHERE TODATE in ( SELECT MAX(TODATE) FROM schema.myTable WHERE HISTTYPE = 'Close' GROUP BY INSTRUMENT );

但是，这给了我同一个乐器的多个，而我只想要其中一个。编辑：

因此，查询后我想要：

priceDate | fromDate | toDate | INSTRUMENT | uniqueID 25/09/2018 25/09/2018 25/09/2018 AUD | 1 26/09/2018 26/09/2018 26/09/2018 EUR | 2 25/09/2018 25/09/2018 25/09/2018 EUR | 3 25/09/2018 25/09/2018 25/09/2018 JPN | 4 29/09/2018 29/09/2018 01/01/6000 EUR | 5 29/09/2018 29/09/2018 01/01/6000 JPN | 6 20/09/2018 20/09/2018 20/09/2018 JPN | 7 28/09/2018 28/09/2018 01/01/6000 AUD | 8

Answer 1

我认为您只需要一个相关的子查询：

UPDATE schema.myTable t
    SET TODATE = TO_DATE('60000101', 'yyyymmdd') 
    WHERE TODATE = ( SELECT MAX(tt.TODATE)
                     FROM schema.myTable tt
                     WHERE tt.HISTTYPE = 'Close' AND
                           tt.INSTRUMENT = t.INSTRUMENT
                   );

Answer 2

如果理解正确，则可以使用row_number窗口功能并找到每组仪器的最大日期，然后进行更新

SET TODATE = TO_DATE('60000101', 'yyyymmdd') 
WHERE TODATE in ( 
select TODATE from
(
SELECT TODATE ,row_number() over(partition by INSTRUMENT order by TODATE desc) as rn FROM schema.myTable WHERE HISTTYPE = 'Close'
) as t where t.rn=1
 );

Oracle SQL。选择最大日期

2 个答案: