如何优化SQL查询当前数据上一条和下一条的记录？

如果ID是主键或者有索引，可以直接查找：

方法1：

select * from table_a where id = (select id from table_a where id < {$id} order by id desc limit 1);

select * from table_a where id = (select id from table_a where id > {$id} order by id asc limit 1);

方法2：

  

select * from table_a where id = (select max(id) from table_a where id < {$id});

select * from table_a where id = (select min(id) from table_a where id > {$id});