Question

我想要报告在特定时期内没有销售的品牌。这是我到目前为止尝试过的方法，但是我得到了一个空列Brand_Name。

SELECT DISTINCT 
    Brands$.BRAND_NAME
FROM
    Brands$
INNER JOIN 
    Products$ ON Brands$.BRAND_ID = Products$.BRAND_ID
LEFT JOIN 
    InvDetails$ ON Products$.PRODUCT_ID = InvDetails$.PRODUCT_ID
INNER JOIN 
    Invoices$ ON Invoices$.INVOICE_ID = InvDetails$.INVOICE_ID
WHERE 
    InvDetails$.PRODUCT_ID IS NULL 
    AND (Invoices$.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' 
                                    AND '2013-11-22 17:54:03.437')

Answer 1

您应在ON子句中移动左连接表的条件

SELECT DISTINCT Brands$.BRAND_NAME
FROM Brands$
INNER JOIN Products$ ON Brands$.BRAND_ID=Products$.BRAND_ID
LEFT JOIN InvDetails$ ON Products$.PRODUCT_ID=InvDetails$.PRODUCT_ID 
        AND InvDetails$.PRODUCT_ID IS NULL
INNER JOIN Invoices$ ON Invoices$.INVOICE_ID=InvDetails$.INVOICE_ID
   AND (Invoices$.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' AND '2013-11-22 17:54:03.437')

如果您将where与左连接表相关的列一起使用，则可以用作内部连接

Answer 2

我认为您只需要两个LEFT JOIN，并将发票上的条件移至ON子句；

SELECT DISTINCT b.BRAND_NAME
    FROM Brands$ b JOIN
         Products$ p
         ON b.BRAND_ID = p.BRAND_ID LEFT JOIN
         InvDetails$ id
         ON p.PRODUCT_ID = id.PRODUCT_ID LEFT JOIN
         Invoices$ i
         ON i.INVOICE_ID = id.INVOICE_ID AND
            i.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' AND '2013-11-22 17:54:03.437'
WHERE id.PRODUCT_ID IS NULL;

表别名使查询更易于编写和阅读。

Answer 3

与此：

SELECT DISTINCT Brands$.BRAND_NAME
FROM Brands$
INNER JOIN Products$ ON Brands$.BRAND_ID = Products$.BRAND_ID
INNER JOIN InvDetails$ ON Products$.PRODUCT_ID = InvDetails$.PRODUCT_ID
INNER JOIN Invoices$ ON Invoices$.INVOICE_ID = InvDetails$.INVOICE_ID
WHERE Invoices$.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' AND '2013-11-22 17:54:03.437'

您获得在特定时期内有销售的产品。
因此，使用EXCEPT：

SELECT Brands$.BRAND_NAME
FROM Brands$
EXCEPT
SELECT DISTINCT Brands$.BRAND_NAME
FROM Brands$
INNER JOIN Products$ ON Brands$.BRAND_ID = Products$.BRAND_ID
INNER JOIN InvDetails$ ON Products$.PRODUCT_ID = InvDetails$.PRODUCT_ID
INNER JOIN Invoices$ ON Invoices$.INVOICE_ID = InvDetails$.INVOICE_ID
WHERE Invoices$.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' AND '2013-11-22

您将获得在此特定时期内没有销售的所有产品。

Answer 4

另外，当尝试从一个表中查找记录而在另一表NOT EXISTS will perform better on SQL Server than LEFT JOIN\IS NULL中没有相应记录时，我发现它传达的意图更加清晰，例如

SELECT  b.BRAND_NAME
FROM    Brands$ AS b
WHERE   NOT EXISTS
        (   SELECT  1
            FROM    Products$ AS p
                    INNER JOIN InvDetails$ AS id
                        ON id.PRODUCT_ID = p.PRODUCT_ID
                    INNER JOIN Invoices$ AS i
                        ON i.INVOICE_ID = id.INVOICE_ID
            WHERE   i.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' AND '2013-11-22 17:54:03.437'
            WHERE   p.BRAND_ID = b.BRAND_ID
        );

在某些情况下，两者之间没有性能差异，但是在这种情况下，我绝对希望NOT EXISTS的性能更好，因为至少您已删除了删除重复记录的需要。

Answer 5

我正在使用NOT EXISTS排除指定时期内带有发票的任何品牌

SELECT DISTINCT b.BRAND_NAME
FROM Brands$ b
INNER JOIN Products$ p ON b.BRAND_ID=p.BRAND_ID
WHERE NOT EXISTS(SELECT 1 
                 FROM Invoices$ i
                 JOIN InvDetails$ id ON i.INVOICE_ID = id.INVOICE_ID
                 WHERE i.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' AND '2013-11-22 17:54:03.437'
                   AND id.PRODUCT_ID = p.PRODUCT_ID)

Answer 6

使用发票查找品牌并排除。

SELECT B.BRAND_NAME FROM Brands$ B
LEFT JOIN (
    SELECT Brands$.BRAND_NAME
        FROM Brands$
        INNER JOIN Products$ ON Brands$.BRAND_ID=Products$.BRAND_ID
        JOIN InvDetails$ ON Products$.PRODUCT_ID=InvDetails$.PRODUCT_ID
        JOIN Invoices$ ON Invoices$.INVOICE_ID=InvDetails$.INVOICE_ID
        WHERE InvDetails$.PRODUCT_ID IS NULL  AND (Invoices$.INVOICE_DATE BETWEEN '2013-10-22 23:41:49.143' AND '2013-11-22 17:54:03.437')
    GROUP BY Brands$.BRAND_NAME ) T ON B.BRAND_NAME  = T.BRAND_NAME
WHERE T.BRAND_NAME IS NULL

与数字名称相比，数字ID必须更快地进行比较。

查询SQL时结果为空

6 个答案: