根據多個訂單選擇行

Question

我的表PURCHASES具有以下列：NAME,ORDER_ID,ITEM_ID。

當客戶訂單2項，則將其記錄與下相同ORDER_ID 2行和兩個相同或不同ITEM_ID（取決於如果客戶已經購買相同的項目或沒有）。

我想選擇所有誰總共不到3項目少於4項所做的（不管它們是相同的）的客戶端。下面是當前的代碼：

SELECT NAME, COUNT(DISTINCT ORDER_ID) AS number_of_orders, COUNT(ITEM_ID) AS number_of_items 
FROM `PURCHASES` 
WHERE number_of_orders <3 
AND number_of_items <4 
GROUP BY NAME 
ORDER BY number_of_items DESC 

我收到以下錯誤信息：Unknown column 'number_of_orders' in 'where clause'

Answer 1

使用該查詢做

SELECT NAME, COUNT(DISTINCT ORDER_ID) AS number_of_orders, COUNT(ITEM_ID) AS 
number_of_items 
FROM `PURCHASES` 
GROUP BY NAME 
HAving COUNT(DISTINCT ORDER_ID) <3 
AND COUNT(ITEM_ID) <4 
ORDER BY number_of_items DESC 

Answer 2

你應該使用子查詢

SELECT * FROM (
    SELECT NAME, COUNT(DISTINCT ORDER_ID) AS number_of_orders, COUNT(ITEM_ID) AS number_of_items) 
FROM `PURCHASES` 
WHERE number_of_orders <3 
    AND number_of_items <4 
GROUP BY NAME 
ORDER BY number_of_items DESC