[英]Query showing exchange rates by date
抱歉,這是一個愚蠢的問題...
我有一個表格,其中包含多種貨幣在不同日期的匯率,如下所示:
+-----------------------------+
| FOREKEY FOREDATE FORERATE |
+-----------------------------+
| 1 01/01/16 1.5 |
| 2 01/01/16 1.9 |
| 3 01/01/16 9.2 |
| 4 01/01/16 1.0 |
| 2 01/02/16 1.7 |
| 3 01/03/16 9.0 |
| 4 01/04/16 1.1 |
+-----------------------------+
我想創建一個查詢,以給出任何給定日期的通行貨幣匯率。
我已經嘗試過下面的查詢,但是例如,這沒有顯示01/03/16的FOREKEY 1匯率。
SELECT
F.FOREDATE,
F.FOREKEY,
F.FORERATE
FROM
FORERATE F
INNER JOIN
(SELECT
MAX(FOREDATE) FOREDATE
FROM
FORERATE
GROUP BY
FOREDATE) FSUB
ON (F.FOREDATE = FSUB.FOREDATE) OR (F.FOREDATE > FSUB.FOREDATE)
任何幫助表示感謝!
您可以在where子句中使用SELECT MAX()
,如下所示:
SELECT
F.FOREDATE,
F.FOREKEY,
F.FORERATE
FROM FORERATE F
WHERE F.FOREDATE = (SELECT MAX(FOREDATE)
FROM FORERATE FMD
WHERE F.FOREKEY=FMD.FOREKEY)
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