如何利用sql 读取辅表的最大max 和第二最大max。。。。

SELECT

  `主表`.id,

  `主表`.title,

  `辅表`.*

FROM

  tableB AS `辅表`

  INNER JOIN tableA AS `主表`

    ON `主表`.id = `辅表`.firm_id

WHERE

#子查询判断该行是否需要取出，最大一条的count为0 次大一条的count为1，其余不满足条件 所以不读取

  (SELECT

    COUNT(`辅表2`.create_time)

  FROM

    tableB AS `辅表2`

  WHERE `主表`.id = `辅表2`.firm_id

    AND `辅表2`.create_time > `辅表`.`create_time`) < 2

ORDER BY `主表`.id,

  `辅表`.create_time DESC 

取最大一条能用max，取第二大的就不需要用max函数了。。。。