问获取每个ID的倒数第二行

EN

SELECT 
   * 
FROM 
   (SELECT 
       @rn:=if(@prv=a_id, @rn+1, 1) as rId,
       @prv:=a_id as a_id,
       ---Remaining columns
   FROM 
       audittable
   JOIN
       (SELECT @rn:=0, @prv:=0) t
   WHERE
       a_id IN (1,2,3,4,5,6,7,8)
   ORDER BY 
       a_id, <column> desc)tmp --Replace column with the column with which you will determine it is the last record
WHERE 
   rId=1;

select at1.* from audittable at1 where 
datecreated in( select max(datecreated) from audittable at2
where 
at1.id = at2.id
order by datecreated desc
);

SELECT MAX(b), *
FROM audittable
GROUP BY a_id