select * from 表 where id = 1；
update 表 set reading = reading =1 where id = 1;
这两条SQL是在一张表中，我要先进行update操作，然后再进行查询操作。
https://blog.csdn.net/ycb1689/article/details/43834445
update table_name set reading = (select reading from table_name t where t.id = 1);