選擇所有客戶，除非他們有其他產品 - SQL

我有兩個表。一個由客戶和另一個由產品，他們已經購買：選擇所有客戶，除非他們有其他產品 - SQL

表客戶

CustID, Name 
    1,  Tom 
    2,  Lisa 
    3,  Fred

表產品

CustID, Item 
    1,  Toaster 
    1,  Breadbox 
    2,  Toaster 
    3,  Toaster

我想獲得所有買了一個烤麪包機的客戶，除非他們還買了一個麪包箱。

所以我曾嘗試以下：

SELECT * FROM Customer 
JOIN Product 
    ON Customer.CustID=Product.CustID 
WHERE Product in 
    (SELECT 
     Item 
    FROM Product 
    WHERE (Item = 'Toaster' AND Item != 'Breadbox'));

和：

SELECT * FROM Customer 
INNER Join Product 
ON Customer.CustID=PRODUCT.CustID 
WHERE Product.Item = 'Toaster' 
AND Product.Item NOT IN ('Breadbox');

但都給出了相同的結果，其中包括湯姆，這不已經擁有一個麪包盒。

我該如何確保只有擁有烤麪包機但不擁有面包箱的客戶才能上市？

來源

2016-03-29 Terjeja

SELECT distinct * FROM Customer 
LEFT JOIN Product ON Customer.CustID=Product.CustID 
WHERE Item = 'Toaster' 
AND Customer.CustID NOT IN (
Select CustID FROM Product Where Item = 'Breadbox' 
)

來源

2016-03-29 19:18:24 wajeeh

如果可能的話，此查詢將返回沒有產品的客戶，因此在我看來您想要內連接。如果可能有多個烤麪包機，這也會多次列出客戶。 – shawnt00

我試過查詢，它的工作正確，你能舉個例子嗎？ @ shawnt00 – wajeeh

我的不好。我誤解了「where」作爲連接條件的一部分。但是，你真的不如寫'內部連接'，因爲這就是你會得到的。 – shawnt00

試試這個：

SELECT c.CustID, c.Name 
FROM customer AS c 
JOIN product AS p ON c.CustID = p.CustID 
GROUP BY c.CustID, c.Name 
HAVING SUM(p.Item = 'Toaster') >= 1 AND SUM(p.Item = 'Breadbox') = 0

來源

2016-03-29 19:16:23

SELECT * FROM Customer C 
LEFT JOIN Product PT ON C.CustID = PT.CustID AND PT.Item = 'Toaster' 
LEFT JOIN Product PB ON C.CustID = PB.CustID AND PB.Item = 'Breadbox' 
WHERE PT.Item IS NOT NULL AND PB.Item IS NULL

來源

2016-03-29 19:21:05

select c.CustID, min(c.Name) as Name 
from Customer c inner join Product p 
    on p.CustID = c.CustID 
where p.Item in ('Toaster', 'Breadbox') 
group by c.CustID 
having 
    max(p.Item) = 'Toaster' and min(p.Item) = 'Toaster'

或

having 
     count(case when p.Item = 'Toaster' then 1 end) > 0 
    and count(case when p.Item = 'Breadbox' then 1 end) = 0

爲你做不嚴格第二種情況需要where雖然它可能有助於在大型演出表。

來源

2016-03-29 19:27:53 shawnt00

這是我的第一篇文章，所以原諒任何失誤。客戶和產品表之間存在「多對一」關係。要制定要應用的邏輯限制，您需要彙總產品表格或加入產品表格兩次。實際上，您正試圖將多對一關係摺疊爲「一對一」關係。

以下是產品表連接兩次的示例。

SELECT DISTINCT 
a.Name 
FROM 
Customer a 
JOIN Product b ON a.CustID = b.CustID 
LEFT JOIN Product c on a.CustID = c.CustID AND c.Item = 'Breadbox' 
WHERE 
b.Item = 'Toaster' AND 
c.CustID IS NULL

或（略微低效率取決於索引）

SELECT DISTINCT 
a.Name 
FROM 
Customer a 
JOIN Product b ON a.CustID = b.CustID 
WHERE 
b.Item = 'Toaster' AND 
NOT EXISTS (SELECT 1 FROM Product c where a.CustID = c.CustID AND c.Item = 'Breadbox')

而且，這裏是產品表中加入一次的例子 - 可能複雜得多，你需要。

SELECT 
a.Name 
FROM 
Customer a 
JOIN 
(
    SELECT 
    CustID, 
    SUM(case when Item = 'Toaster' then 1 else 0 end) sum_Toaster, 
    SUM(case when Item = 'Breadbox' then 1 else 0 end) sum_Breadbox 
    FROM 
    Product 
    WHERE 
    Item in ('Toaster','Breadbox') 
    GROUP BY 
    CustID 
    HAVING 
    SUM(case when Item = 'Toaster' then 1 else 0 end) > 0 AND 
    SUM(case when Item = 'Breadbox' then 1 else 0 end) = 0 
) b ON a.CustID = b.CustID

來源

2016-03-29 19:50:32 Andy

選擇所有客戶，除非他們有其他產品 - SQL

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