從另一個表

Question

插入數據我有兩個表：

股票數據

Batch Stock Rate 
------------------------ 
123---ABC---123 
251---XYZ---50 
250---XYZ---55 
247---XYZ---48 
118---ABC---120 
310---PQR---77 
309---PQR---76 

，第二個表 訂單簿

Date-------Stock---qty--Rate 
-------------------------- 
2016-01-01---ABC---10---Null 
2016-01-02---XYZ---25---Null 
2016-01-03---PQR---18---Null 
2016-01-04---XYZ---50---Null 

我堅持的順序插入率從庫存數據中預訂表格，其中庫存數據中的比率應該是每個產品的最新批次。在此先感謝

Answer 1

嘗試此查詢： -

UPDATE order_book ob, (
      SELECT rate, stock 
      FROM stock_data sd 
      GROUP BY stock 
      HAVING MAX(batch) 
      ORDER BY batch DESC 
    ) result 
SET ob.rate = result.rate 
WHERE ob.stock = result.stock 

Answer 2

請嘗試以下查詢：

UPDATE OrderBook OB 
INNER JOIN (
    SELECT 
     SD.Stock, 
     SD.Rate 
    FROM StockData SD 
    INNER JOIN (
     SELECT 
      Stock, 
      MAX(Batch) max_batch 
     FROM StockData 
     GROUP BY Stock 
    ) AS t 
    ON SD.Stock = t.Stock AND SD.Batch = t.max_batch 
) AS maxBatchRateTable 
ON OB.Stock = maxBatchRateTable.Stock 
SET OB.Rate = maxBatchRateTable.Rate; 

說明：

這個查詢

SELECT 
     SD.Stock, 
     SD.Rate 
    FROM StockData SD 
    INNER JOIN (
     SELECT 
      Stock, 
      MAX(Batch) max_batch 
     FROM StockData 
     GROUP BY Stock 
    ) AS t 
    ON SD.Stock = t.Stock AND SD.Batch = t.max_batch 

發現從最新一批每隻股票的速度。

以後如果你做這個表，你OrderBook表之間的INNER JOIN匹配Stock並通過上面的查詢，你會得到你想要的返回值rate更新OrderBook表Rate。

Answer 3

UPDATE 
    order_book 
INNER JOIN 
    (
     SELECT 
     Rate, 
     Stock 
     FROM 
     stock_data 
     INNER JOIN 
     (
      SELECT 
       MAX(Batch) AS batch, 
       stock  
      FROM 
       stock_data  
      GROUP BY 
       Stock 
     ) AS latestBatch  
      ON stock_data.Batch = latestBatch.batch 
      AND stock_data.stock = latestBatch.stock 
     ) AS updateData 
      ON updateData.Stock = order_book.Stock 
     SET 
     order_book.Rate = updateData.Rate 

應該是沿着這些線路