Mysql函数count（）单独计算行数

Question

我有以下查询，其中我想获得总行数，但这似乎在每个单独计算这里是查询和结果

SELECT
     COUNT(pc.product_id)
FROM
    products as p
INNER JOIN product_categories as pc
ON p.product_id = pc.product_id AND pc.subcategory_id IN (77)   
GROUP BY pc.product_id
HAVING COUNT(pc.subcategory_id) = 1

结果是：

COUNT（pc.product_id）

1

1

1

......但它应该是

COUNT（pc.product_id）

3

更新

上述查询应计算此查询获得的产品数量

SELECT
    *
FROM
    products as p
INNER JOIN product_categories as pc
ON p.product_id = pc.product_id AND pc.subcategory_id IN ($sb_2)   
GROUP BY pc.product_id
HAVING COUNT(DISTINCT pc.subcategory_id) = $sb_count 

$sb_2 = 77,76;
$sb_count = how many values are in $sb_2;

77 and 76 are different subcategories ids but are common for some products

如果您知道另一种计算方法或进行其他查询......

Answer 1

SELECT
     COUNT(pc.product_id)
FROM
    products as p
INNER JOIN product_categories as pc
ON p.product_id = pc.product_id AND pc.subcategory_id IN (77)
HAVING COUNT(pc.subcategory_id) = 1

删除组应该可以解决问题。

Answer 2

我设法按以下查询计算行数。

"SELECT COUNT(*) as count FROM (SELECT
    *
FROM
  product_categories WHERE subcategory_id IN (77,76)   
GROUP BY product_id
HAVING COUNT(DISTINCT subcategory_id) = 2) as subc";
}