MySQL自动递增编号顺序在运行insert select时存在间隙

我在SQL下面运行

INSERT INTO project (project_id, works_no, project_name, project_location, project_owner, head_contractor, site_project_manager, project_manager_phone, created_time, created_by, company_id, lmd, project_status)
SELECT NULL AS project_id, works_no, project_name, project_location, project_owner, head_contractor, site_project_manager, project_manager_phone, '2020-10-16', '100', '3', '$2020-10-16', 'A'
FROM sample_project;

但是，当我检查数据库时，似乎缺少自动递增顺序。如果源表中有更多记录，则自动增量间隔也会增加

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这有什么原因吗。我仍然找不到任何参考资料。

这很正常。不要担心差距。（虽然如果您使用InnoDB引擎而不是MyISAM，这种可能性会降低）绝对不能保证

auto_increment

列没有间隙。它保证是独一无二的。例如，见：