如何根据 table2 中的某些特定列在 table1 中获取 COUNT

Question

我有以下 tables:

Post Table

+----+------------+--------------+
| id | is_deleted | is_published |
+----+------------+--------------+
| 1  |     0      |      1       |
| 2  |     0      |      1       |
| 3  |     0      |      1       |
| 4  |     0      |      0       |
| 5  |     1      |      1       |
+----+------------+--------------+l

标签Table

+----+---------+
| id |   name  |
+----+---------+
| 1  | Fashion |
| 2  | Tech    |
+----+---------+

Post_Tag Table

+----+--------+---------+
| id | tag_id | post_id |
+----+--------+---------+
| 1  |   2    |    2    |
| 2  |   2    |    3    |
| 3  |   1    |    2    |
| 3  |   1    |    4    |
| 3  |   1    |    1    |
| 4  |   1    |    5    |
+----+--------+---------+

由上面的tables，tags和posts的关系存储在post_tagtable。使用 post_tag table，我想计算有多少 post 绑定到标签 .所以我写了这个查询来计算时尚标签的 posts：

SELECT COUNT(tp.id) as totalPost FROM `post_tags` tp WHERE tag_id = 1;

这导致这对时尚标签是正确的：

+-----------+
| totalPost |
+-----------+
|    4      |
+-----------+

现在，我的挑战是：

post 与 is_deleted 列 = true 不应计算在内。
post 与 is_published 列 = false 不应计算在内。
如果 post 同时具有 is_deleted 和 is_published列为true，不应计算在内。

因此，只有当 post is_published = true 和 is_deleted = false.

请问，我该如何实现这些？

Answer 1

您必须 JOIN 表并使用 WHERE 子句过滤掉行。

SELECT COUNT(tp.id) as totalPost
FROM post_tags tp
JOIN post p ON tp.post_id = p.id
WHERE tag_id = 1
AND p.is_deleted = 0
AND p.is_published = 1;

如何根据 table2 中的某些特定列在 table1 中获取 COUNT

How can I get COUNT in table1 based on some specific columns in table2

mysql

database

doctrine