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我在查詢MySQL。說我有3個表和想象中的數據是這樣的:在日期範圍內加入MySQL
apples_sold
+--------+------------+----------+------+
| tranID | date | apple_id | sold |
+--------+------------+----------+------+
| 101 | 2012-07-01 | a01 | 2 |
| 102 | 2012-07-02 | a01 | 5 |
| 103 | 2012-07-03 | a01 | 1 |
| 104 | 2012-07-04 | a01 | 0 |
| 105 | 2012-07-05 | a01 | 2 |
+--------+------------+----------+------+
price_history
+---------+------------+----------+-------+
| priceID | date | apple_id | price |
+---------+------------+----------+-------+
| p01 | 2012-07-01 | a01 | $0.25 |
| p02 | 2012-07-03 | a01 | $0.10 | <- price change
+---------+------------+----------+-------+
apple_name
+----------+----------+
| apple_id | name |
+----------+----------+
| a01 | McIntosh |
+----------+----------+
試圖創建輸出這樣的查詢:
apple_prices
+------------+----------+-------+
| date | name | price |
+------------+----------+-------+
| 2012-07-01 | McIntosh | $0.25 |
| 2012-07-02 | McIntosh | $0.25 |
| 2012-07-03 | McIntosh | $0.10 | <- price change
| 2012-07-04 | McIntosh | $0.10 |
| 2012-07-05 | McIntosh | $0.10 |
+------------+----------+-------+
沒有希望的價格存儲與apples_sold記錄,正常化和所有。問題在於我不能確定將銷售記錄與價格結合的最佳方式。
加入與apple_id – 2012-07-22 00:05:29
3個表,你可以在priceID存儲在apples_sold表,然後加入就可以了 – Vatev 2012-07-22 00:14:51
你可以改變你的數據結構?您的價格歷史記錄表格是緩慢變化維度的示例。當每條記錄上都有生效日期和結束日期時,查詢更容易。 – 2012-07-22 17:07:53