我有一个如下所示的select语句:
SELECT DISTINCT category_name
FROM categories c JOIN products p
ON c.category_id = p.category_id
ORDER BY category_name;
返回:
+---------------+
| category_name |
+---------------+
| Basses |
| Drums |
| Guitars |
+---------------+
我试图使用子查询获得相同的结果,但我没有得到完全相同的结果。以下是我使用的代码:
SELECT DISTINCT category_name FROM
categories WHERE category_name IN(SELECT distinct
category_name FROM products) ORDER BY category_name;
当我运行此代码时,我得到:
+---------------+
| category_name |
+---------------+
| Basses |
| Brass |
| Drums |
| Guitars |
| Keyboards |
+---------------+
我错误的是我没有得到相同的输出?