Mysql SQL子集查询

我在为SQL表创建查询时遇到问题。我试图创建的查询显示“衣服”类别内的产品数量，而不显示附件，例如输入为T恤或运动衫的产品列表

以下是已创建的表：

CREATE DATABASE IF NOT EXISTS product_list;

DROP TABLE IF EXISTS products;
DROP TABLE IF EXISTS product_categories;
DROP TABLE IF EXISTS categories;

CREATE TABLE products (
    product_id INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(50) DEFAULT NULL,
    active BOOL DEFAULT NULL
);

CREATE TABLE categories (
    category_id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(50),
    structure VARCHAR(50)
);

CREATE TABLE product_categories (
    product_id INT,
    category_id INT,
    PRIMARY KEY(product_id, category_id)
);

INSERT INTO products VALUES
(NULL, "Blue Sweatshirt", false),
(NULL, "Short Sleeve T-Shirt", true),
(NULL, "White Vest", true),
(NULL, "Black Hairclip", true),
(NULL, "Knitted Hat", false),
(NULL, "Grey Sweatshirt", true),
(NULL, "Tartan Scarf", true);

INSERT INTO categories VALUES
(NULL, "Sweatshirts", "Clothes>Sweatshirts"),
(NULL, "T-Shirts", "Clothes>T-Shirts"),
(NULL, "Accessories", "Accessories"),
(NULL, "Winter", "Clothes>Winter"),
(NULL, "Vests", "Clothes>Vests");

INSERT INTO product_categories VALUES
(1, 1), (2, 2), (3, 5), (3, 4), (4, 3), (5, 3), (5, 4), (6, 1), (7, 3), (7, 4);

请尝试此查询

select * from products a
join Product_categories b on a.product_id=b.product_id
join categories c on b.category_id=b.category_id
where c.name like '%Clothes%'

---

如果我理解正确，这是一个集合内集合查询。您正在寻找至少有一个“衣服”类别的产品，并且所有类别都不是衣服。我使用

groupby

和

have

来实现这一点，因为它非常灵活：

select pc.product_id
from Product_categories pc join
     categories c
     on pc.category_id = c.category_id
group by pc.product_id
having sum(case when c.structure like 'Clothes%' then 1 else 0 end) > 0 and
       sum(case when c.structure not like 'Clothes%' then 1 else 0 end) = 0;

如果只需要计数，则可以将其用作子查询并使用

count（*）

编辑：

一张小纸条。这个问题现在用MySQL标记，MySQL方便地简写了

having

子句：

having sum(c.structure like 'Clothes%') > 0 and
       sum(c.structure not like 'Clothes%') = 0;

---

您的示例数据的预期结果集是什么？基于DDL，这似乎是一个MySQL问题，请对其进行相应的标记。预期结果是获得服装类别内的产品列表。我使用一个模板表来学习查询，并被引导相信它是SQL。谢谢，我写的问题很奇怪，所以我为任何混淆道歉。