mysql - 带有 SQL 代码的错误消息

Question

我需要一些关于 MySQL 服务器代码的帮助。我不断收到此错误:

执行SQL失败:SQL

SELECT 
    CONCAT(INSTRUCTOR.FIRST_NAME, INSTRUCTOR.LAST_NAME) AS INSTRUCTOR_NAME, 
FROM 
    INSTRUCTOR 
LEFT JOIN 
    APPROVED_INSTRUCTOR 
    ON INSTRUCTOR.INSTRUCTOR_ID=APPROVED_INSTRUCTOR.INSTRUCTOR_ID 

UNION 

SELECT 
    CONCAT(INSTRUCTOR.FIRST_NAME, INSTRUCTOR.LAST_NAME) AS INSTRUCTOR_NAME, 
FROM 
    INSTRUCTOR 
RIGHT JOIN 
    APPROVED_INSTRUCTOR 
    ON INSTRUCTOR.INSTRUCTOR_ID=APPROVED_INSTRUCTOR.Instructor_ID;

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM INSTRUCTOR LEFT JOIN APPROVED_INSTRUCTOR ON INSTRUCTOR.INSTRUCTOR_ID=APPROV' at line 1

我仔细检查了表名和字段名，并进行了大约一个小时的研究，但我阅读的所有内容都表明代码没有问题。

Answer 1

删除 INSTRUCTOR_NAME 两次出现后的逗号:

这个:

SELECT CONCAT(INSTRUCTOR.FIRST_NAME, INSTRUCTOR.LAST_NAME) AS INSTRUCTOR_NAME,

应该是:

SELECT CONCAT(INSTRUCTOR.FIRST_NAME, INSTRUCTOR.LAST_NAME) AS INSTRUCTOR_NAME