查询最后一个主键id
SELECT IF(MAX(id) IS NULL, 0, MAX(id)) AS maxid FROM users;
查询最小的主键id
SELECT IF(MIN(id) IS NULL, 0, MIN(id)) AS minid FROM users;
获得一个新的自增id
SELECT IF(MAX(id) IS NULL, 0, (MAX(id) + 1)) AS newid FROM users;
查询最后一条插入的数据
SELECT * FROM users WHERE id = (
SELECT IF(MAX(id) IS NULL, 0, MAX(id)) AS maxid FROM users
);