Question

大家好我需要通过告诉用户进行搜索，按名称或价格进行搜索

SELECT        
   BID.BiddingPrice, BID.Date, Item.Name
FROM            
   BID 
INNER JOIN
   Buyer ON BID.BuyerID = Buyer.BuyerID 
INNER JOIN
   Member ON Buyer.MemberID = Member.MemberID 
INNER JOIN
   Auction ON BID.AuctionID = Auction.AuctionID 
INNER JOIN
   Item ON Auction.ItemID = Item.ItemID
WHERE        
   (Auction.Status = 'Expired') 
   AND (BID.Date BETWEEN @from AND @to) 
   OR (BID.Status = 'Available') 
   OR (Member.Username = @username) 
   OR (BID.BiddingPrice = @price) 
   OR (Item.Name = @name)

Answer 1

我已经强调了我认为实现您正在寻找的结果所需的更改。您需要根据用户提供的内容传递price或name的值，并为其他值传递NULL。例如，name ='Ron'，price = NULL。

SELECT        BID.BiddingPrice, BID.Date, Item.Name
FROM            BID INNER JOIN
                     Buyer ON BID.BuyerID = Buyer.BuyerID INNER JOIN
                     Member ON Buyer.MemberID = Member.MemberID INNER JOIN
                     Auction ON BID.AuctionID = Auction.AuctionID INNER JOIN
                     Item ON Auction.ItemID = Item.ItemID
WHERE        (Auction.Status = 'Expired') AND (BID.Date BETWEEN @from AND @to) **AND**
                     (BID.Status = 'Available') **AND**
                     (Member.Username = @username) **AND**
                     **CASE WHEN @Price IS NOT NULL THEN
                         (BID.BiddingPrice = @price) ELSE
                         (Item.Name = @name) 
                     END**

Answer 2

SELECT BID.BiddingPrice, BID.Date, Item.Name
FROM  BID 
INNER JOIN Buyer ON BID.BuyerID = Buyer.BuyerID 
INNER JOIN Member ON Buyer.MemberID = Member.MemberID 
INNER JOIN Auction ON BID.AuctionID = Auction.AuctionID 
INNER JOIN Item ON Auction.ItemID = Item.ItemID
WHERE        
Auction.Status = 'Expired'
AND (BID.Date BETWEEN @from AND @to)
OR BID.Status = 'Available' 
OR Member.Username = @username
OR(
   (Item.Name = @name OR  @name is null) 
OR (BID.BiddingPrice = @price OR  @price is null)
)

如果任何@parameter可以为null，那么你应该创建你的where子句，如：

 WHERE        
    Auction.Status = 'Expired'
    AND (BID.Date>= @from OR @from is null) 
    AND (BID.Date<= @to OR @to IS NULL)
    OR BID.Status = 'Available' 
    OR (Member.Username = @username OR @username is null) 
    OR(
       (Item.Name = @name OR  @name is null) 
    OR (BID.BiddingPrice = @price OR  @price is null)
    )

Answer 3

虽然可以通过巧妙地“打开和关闭”WHERE子句的某些部分（如其他答案所示）在静态查询中完成此操作，但请注意这样做的潜在性能影响 - DBMS可能无法制定最佳查询计划。

这是dynamic SQL可能更合适的其中一种情况。使用动态SQL并不意味着你应该停止使用绑定参数！

使用SQL语句和OR运算符进行搜索

3 个答案: