SQL查找按類別的過期產品數和產品總數

Question

我有一個SQL查詢問題。

這是我的產品表：

產品
• ID
• 名稱
• 價錢
•已過期
•fk_category

我想要過期的產品數量和按類別分組的產品總數。

我編寫以下查詢，但很難完成它：

SELECT COUNT(id) as nb_expired, COUNT (id) as nb_product
FROM product
WHERE expired = 1
GROUP BY fk_category;

你能幫我嗎？

Answer 1

您可以在count中僅使用一個case語句來過期：

SELECT sum(case when expired = 1 then 1 else 0 end) as nb_expired
,      COUNT (id) as nb_product
FROM   product
GROUP
BY     fk_category

Answer 2

SELECT fk_category, sum(case when expired = 1 then 1 else 0 end) as expired_count,
COUNT (1) as total 
FROM   product 
GROUP BY     fk_category