在ID列中使用IN语句并检索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
)

显然它不会检索任何数据，因为内部查询检索两列（product_id和count）。 但我也需要伯爵，因为我以后会用它来做一些数学。 如何使用count（*）来使用此IN查询？

谢谢！

Answer 1

加入他们：

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

或者当您的DBMS支持时，使用select子句中的子查询：

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

Answer 4

这可能对您有用：

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