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Mysql 相邻两行记录某列的差值方法

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表结构:

数据:

需求:

按照company_id不同分组,然后分别求出相同company_id相邻记录touch_time的差值

SQL:

select r1.company_id,
 r1.touch_time,
 r2.touch_time,
 r1.touch_time - r2.touch_time
 from (select (@rownum := @rownum + 1) as rownum,
  info.company_id,
  info.touch_time
  from sys_touch_info info, (select @rownum := 0) r
  where info.touch_time is not null
  order by info.company_id) r1
 left join (select (@index := @index + 1) as rownum,
   info.company_id,
   info.touch_time
  from sys_touch_info info, (select @index := 0) r
  where info.touch_time is not null
  order by info.company_id) r2
 on r1.company_id = r2.company_id
 and r1.rownum = r2.rownum - 1

结果:

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