sql语法问题

sql语法如下所示：

SELECT y.NAME, y.EMAIL, k.DATE, k.WORK_NR, k.SCORE, k.FILENAME
FROM bas1.students y, bas1.assignments k, bas1.topics a
WHERE y.ID = k.student_id AND k.topic_id = a.id
WHERE a.NAME = 'History';

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但是我有一些错误，有什么想法吗？

你在哪里用了两次

SELECT y.NAME, y.EMAIL, k.DATE, k.WORK_NR, k.SCORE, k.FILENAME
FROM bas1.students y, bas1.assignments k, bas1.topics a
WHERE y.ID = k.student_id AND k.topic_id = a.id
AND a.NAME = 'History';

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更改为此

您不需要join语句吗？例如：

SELECT y.NAME, y.EMAIL, k.DATE, k.WORK_NR, k.SCORE, k.FILENAME
FROM bas1.students y JOIN bas1.assignments k ON y.ID = k.student_id 
JOIN bas1.topics a ON k.topic_id = a.id
WHERE a.NAME = 'History';