强制使用指定索引为啥一直说指定索引不存在 明明存在的呀？

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#1 Created at ... [Delete] [Delete and Lock User]

SELECT * FROM students FORCE INDEX (score) WHERE class_id = 1 ORDER BY id DESC;

报错ERROR 1176 (42000): Key 'score' doesn't exist in table 'students'

#2 Created at ... [Delete] [Delete and Lock User]

注意是索引的名字，建议创建索引时名字要起好，不要和列重名，推荐idx_score这样的名字

#3 Created at ... [Delete] [Delete and Lock User]

列score存在，索引idx_score还不存在，需要先添加索引

ALTER TABLE students ADD INDEX idx_score (score);

#4 Created at ... [Delete] [Delete and Lock User]

好问题好回答哦