在ID列中使用IN語句並檢索c​​ount（*）？

Question

我有以下SQL命令：

SELECT * from products 
WHERE id IN (
    SELECT product_id, count(*) 
    FROM account_products 
    GROUP BY product_id 
) 

顯然它不獲取任何數據，因爲內部查詢檢索兩列（產品和計數）。 但是我也需要計數，因爲我將在稍後使用它來進行一些數學計算。 如何使用count（*）也可以使用這個IN查詢？

謝謝！

Answer 1

加入他們的行列：

select products.*, t.product_count 
from products 
    join (
    SELECT product_id, count(*) as product_count 
    FROM account_products 
    GROUP BY product_id 
) as t on t.product_id = products.id 

Answer 2

select products.*, count(account_products.product_id) 
from products join account_products on 
    products.product_id = products.id 
group by products.* (obviously all products-fields) 

Answer 3

或用SELECT子句中的子查詢，當你的DBMS支持它：

SELECT 
    products.*, 
    (SELECT count(*) FROM account_products ap WHERE ap.product_id = products.id) as "Number of Accounts" 
from products 

Answer 4

這可能會爲你工作：

WITH MyAccountProducts AS 
(
    SELECT product_id, count(*) AS CountOfAccountProducts 
    FROM account_products 
    GROUP BY product_id 
) 
SELECT p.*,ap.CountOfAccountProducts 
from products AS p 
INNER JOIN MyAccountProducts AS ap ON p.id=ap.product_id