数据库问题记录：MySQL 如何快速查出缺失数据的主键 id？

运行sql，注意将表和主键id进行相对应的替换！

SELECT a.id+1 AS start, MIN(b.id) - 1 AS end
    FROM testtable AS a, testtable AS b
    WHERE a.id < b.id
    GROUP BY a.id
    HAVING start < MIN(b.id)