Question

我的SQL查询正在吐出3000个查询，当它应该吐出20时，我正在使用Oracle。

以下是表格：

Item (itemNumber, itemName, itemDescription, itemValue, itemLocation, 
categoryID, sellerUsername)   

Auction (auctionNumber, currency, startDateTime, endDateTime, shippingTerms, 
startBidAmount, reserveAmount, bidIncrementAmount, noOfItems, itemSold, 
itemNumber feedbackDateAndTime, rating, comments, paymentDate, paymentid)

Bid (bidderUsername, auctionNumber, bidDateTime,bidAmount)

和我的查询

SELECT
   i.itemname,
   i.itemdescription,
   i.itemvalue,
   CASE
       WHEN i.itemnumber=a.itemnumber and a.itemSold='y' THEN 'Sold'
       WHEN a.auctionnumber != b.auctionnumber and TO_CHAR(sysdate,'DD-MON-YY')>endDateTime THEN 'No Bids on that closed auction'
       WHEN TO_CHAR(sysdate,'DD-MON-YY')<a.endDatetime and a.auctionnumber=b.auctionnumber 
                 and reserveamount>(
                 SELECT b.bidAmount
                 FROM dbf12.bid b, dbf12.auction a               
                 WHERE a.auctionnumber=b.auctionnumber 
                 GROUP BY b.bidAmount
                 HAVING b.bidAmount= max(b.bidAmount)) THEN 'No Bids that meets the reserve'
        ELSE 'Auction Still Open'
   END 
FROM 
   dbf12.item i, dbf12.auction a, dbf12.bid b;

Answer 1

您似乎忘记了dbf12.item，dbf12.auction和dbf12.bid之间的连接条件。这使得它基本上是三个表的交叉乘积，将每个表中的每一行连接到所有其他行中的每一行。

尝试这样的事情：

SELECT
   i.itemname,
   i.itemdescription,
   i.itemvalue,
   CASE
       WHEN i.itemnumber=a.itemnumber and a.itemSold='y' THEN 'Sold'
       WHEN a.auctionnumber != b.auctionnumber and TO_CHAR(sysdate,'DD-MON-YY')>endDateTime THEN 'No Bids on that closed auction'
       WHEN TO_CHAR(sysdate,'DD-MON-YY')<a.endDatetime and a.auctionnumber=b.auctionnumber 
                 and reserveamount>(
                 SELECT b.bidAmount
                 FROM dbf12.bid b, dbf12.auction a               
                 WHERE a.auctionnumber=b.auctionnumber 
                 GROUP BY b.bidAmount
                 HAVING b.bidAmount= max(b.bidAmount)) THEN 'No Bids that meets the reserve'
        ELSE 'Auction Still Open'
   END 
FROM 
   dbf12.item i, dbf12.auction a, dbf12.bid b
    WHERE i.itemnumber = a.itemnumber and b.actionnumber = a.auctionnumber

你也可以这样说：

SELECT
   i.itemname,
   i.itemdescription,
   i.itemvalue,
   CASE
       WHEN i.itemnumber=a.itemnumber and a.itemSold='y' THEN 'Sold'
       WHEN a.auctionnumber != b.auctionnumber and TO_CHAR(sysdate,'DD-MON-YY')>endDateTime THEN 'No Bids on that closed auction'
       WHEN TO_CHAR(sysdate,'DD-MON-YY')<a.endDatetime and a.auctionnumber=b.auctionnumber 
                 and reserveamount>(
                 SELECT b.bidAmount
                 FROM dbf12.bid b, dbf12.auction a               
                 WHERE a.auctionnumber=b.auctionnumber 
                 GROUP BY b.bidAmount
                 HAVING b.bidAmount= max(b.bidAmount)) THEN 'No Bids that meets the reserve'
        ELSE 'Auction Still Open'
   END 
    from db12.item i
        inner join dbf12.auction a on a.itemnumber = i.itemnumber
        inner join dbf12.bid b on b.auctionnumber = a.auctionnumber

Oracle查询链接查询

1 个答案: