Question

我正在尝试使用listings表中最高bidder_ID的{{1}}表的buyer_ID列自动更新。我的问题是......如何从bids表中获取与bid_listing相关的listing_ID？

我当前的事件查询：

listing

出价架构

CREATE EVENT updateAuction
ON SCHEDULE EVERY 1 MINUTE
DO
    SET buyer_ID = (SELECT MAX(bidder_ID) FROM bids WHERE bid_listing = (Need each listing_ID from the listings table here)) 
    FROM listings
    WHERE list_expires < now()
    AND buyer_ID = NULL

列表架构

bid_ID bid_listing bidder_ID bid_amount

Answer 1

基于代码示例和您的“出价表中出价最高的ID”的声明

我认为你需要的是 UPDATE JOIN

In [18]: df.Name.tolist()
Out[18]: [u'Christine', u'Alex', u'Brian', u'Thomas', u'Tom']

In [19]: df.Name.str.encode('latin-1', 'ignore').tolist()
Out[19]: ['Christine', 'Alex', 'Brian', 'Thomas', 'Tom']

以下是 UPDATE JOIN 的另一个示例，使用SUB QUERIES获取出价金额最高的bidder_id。

Update listings set
   buyer_id = table2.max_bidder
From listings table1
Inner Join ( Select bids.listing_ID
                  , max(bids.bidder_ID) as max_bidder 
             From bids
             Group by listing_ID ) table2
        on ( table1.listing_ID = table2.listing_ID )
WHERE list_expires < now()
    AND buyer_ID is NULL

我希望它有所帮助

此致

每分钟更新列表的活动

1 个答案: