使用类别过滤器 sql 显示文章

Question

我想选择包含我正在使用 typeorm ( SQL ) 的特定类别的文章 假设我有

articleTable: [
    {
      id: 1,
      title: 'string'
    },
    {
      id: 2,
      title: 'string'
    }
];

categoryTable: [
    {
      id: 1,
      title: 'string'
    }, {
      id: 2,
      title: 'string'
    }
]

article_categories: [
    {
      categoryId: 1,
      articleId: 2
    },{
      categoryId: 1,
      articleId: 1
    },{
      categoryId: 2,
      articleId: 2
    }
]

所以问题是我想选择所有具有确切类别 = [1,2] 等的文章 这意味着如果一篇文章只有类别 1，我不想选择它。

使用此查询，我得到了结果，但它的 id 不完全匹配，而是返回分别具有 id 1 和 2 的文章

async filterData(filterArticleDto: FilterArticlesDto, categoryIds: number[]) {
const qb = this.createQueryBuilder('article');
qb.distinct(true);
if (categoryIds.length) {
  qb.innerJoin(
    'article.categories',
    'categories',
    `categories.category IN (:...ids)`,
    {
      ids: categoryIds,
    },
  );
  qb.leftJoinAndSelect('categories.category', 'catsData');
}
qb.take(filterArticleDto.limit);
return await qb.getMany();

}

Answer 1

原始 sql 查询

SELECT article.*
FROM articles AS article
WHERE EXISTS
  (SELECT count(DISTINCT category_id)
  FROM article_categories AS subcts
  WHERE subcts.article_id = article.id
   AND subcts.category_id IN (1,
                              2)
 HAVING count(DISTINCT category_id) = 2)

https://dbfiddle.uk/?rdbms=postgres_12&fiddle=86f8d3a8bdc9248a918a4c37d8da5ea0

或

SELECT article.*
FROM articles AS article
INNER JOIN
(SELECT article_id,
      array_agg(category_id) AS cts
FROM article_categories
GROUP BY article_id) AS category ON article.id = category.article_id
WHERE ARRAY[1,
        2::integer] = category.cts

https://dbfiddle.uk/?rdbms=postgres_12&fiddle=fdde52c1d11d69b690f9fe9345272786