MySql Select查詢合併結果

Question

嗨即時通訊有2個客戶和customer_items。 現在有在第二個表兩個表的CUSTOMER_ID每個客戶可以有多個項目，因此該表可以是這樣的

id   | item 
---------------------------- 
1501   | pillow 
1501   | blanket 
1501   | others 
1502   | pillow 
1502   | blanket 
1502   | others 

現在我怎麼能與一個MySQL查詢選擇具有兩個枕頭和毛毯客戶

這是我最後的辦法

select custlist.id FROM customers custlist LEFT JOIN customer_items custitems ON custitems.id=custlist.id WHERE (custitems.items='pillow' AND custitems.items='blanket') UNION ALL 

Answer 1

這是一個Relational Division問題。

SELECT a.customer_ID 
FROM customers a 
     INNER JOIN customer_items b 
      ON a.customer_ID = b.customer_ID 
WHERE b.item IN ('pillow', 'blanket') 
GROUP BY a.customer_ID 
HAVING COUNT(*) = 2 

• SQL of Relational Division

如果item不是每個customer_ID獨特，一DISTINCT關鍵字是需要計算的唯一記錄。由JW上述溶液的

SELECT a.customer_ID 
FROM customers a 
     INNER JOIN customer_items b 
      ON a.customer_ID = b.customer_ID 
WHERE b.item IN ('pillow', 'blanket') 
GROUP BY a.customer_ID 
HAVING COUNT(DISTINCT b.item) = 2 

Answer 2

輕微變化： - 如果你想客戶名稱則剛剛加入的客戶表

SELECT a.customer_ID 
FROM customers a 
INNER JOIN (SELECT customer_ID, item FROM customer_items WHERE item = 'pillow' GROUP BY customer_ID) PillowCheck 
ON a.customer_ID = PillowCheck.customer_ID 
INNER JOIN (SELECT customer_ID, item FROM customer_items WHERE item = 'blanket' GROUP BY customer_ID) BlanketCheck 
ON a.customer_ID = PillowCheck.customer_ID 

Answer 3

嘗試此查詢

SELECT 
    a.id 
FROM 
    customer_items a 
INNER JOIN 
    customer_items b 
ON 
    a.id= b.id and 
    a.item = 'PILLOW' AND 
    b.item='blanket' 

。如果客戶有多個枕頭或毯子然後添加distinct

Answer 4

SELECT 不同CUSTOMER_ID，項 FROM customer_items WHERE在（ '枕頭'， '毯'） GROUP BY CUSTOMER_ID HAVING COUNT（項目）= 2

項