mysql - SQL错误 "Every derived table must have its own alias"

Question

这个问题已经有答案了:

What is the error "Every derived table must have its own alias" in MySQL? (4 个回答)

已关闭 5 年前。

这是我的 SQL 查询。

SELECT MAX(course_id), sec_id, COUNT(ID) 
FROM (SELECT MAX(course_id), sec_id, COUNT(ID) 
      FROM section 
      NATURAL JOIN takes 
      GROUP BY course_id);

执行时，我收到此错误:

<"Every derived table must have its own alias">

Answer 1

向派生表添加别名。

SELECT 
    MAX(course_id), 
    sec_id, 
    COUNT(ID) 
FROM 
    (
        SELECT 
            MAX(course_id), 
            sec_id, 
            COUNT(ID) 
        FROM 
            section NATURAL 
            JOIN takes 
        GROUP BY 
            course_id
    ) `A`;