有个select,要根据六个时间字段中最大的一个来进行排序,最新的记录排在最前面. 请问 怎么写这个sql语句?
名称 time1 time2 time3 time4 time5 time6
name1 2006-11-14 2006-11-4 2006-10-4 2006-11-24 2006-08-4 2006-11-4
name7 2006-10-2 2006-10-12 2006-10-6 2006-10-13 2006-10-12 2006-10-12
name3 2006-10-25 2006-10-4 2006-10-19 2006-10-19 2006-10-31 2006-10-25
name5 2006-11-25 2006-12-9 2006-09-10 2006-10-19 2006-10-31 2006-10-25
name2 2006-10-25 2006-10-5 2006-10-19 2006-10-19 2006-10-3 2006-12-25
name9 2006-10-25 2006-10-4 2006-10-19 2006-11-19 2006-11- 1 2006-10-25name1 最大时间是11-24
name7 10-13
name3 10-31
......
根据最大时间来进行排序
名称 time1 time2 time3 time4 time5 time6
name1 2006-11-14 2006-11-4 2006-10-4 2006-11-24 2006-08-4 2006-11-4
name7 2006-10-2 2006-10-12 2006-10-6 2006-10-13 2006-10-12 2006-10-12
name3 2006-10-25 2006-10-4 2006-10-19 2006-10-19 2006-10-31 2006-10-25
name5 2006-11-25 2006-12-9 2006-09-10 2006-10-19 2006-10-31 2006-10-25
name2 2006-10-25 2006-10-5 2006-10-19 2006-10-19 2006-10-3 2006-12-25
name9 2006-10-25 2006-10-4 2006-10-19 2006-11-19 2006-11- 1 2006-10-25name1 最大时间是11-24
name7 10-13
name3 10-31
......
根据最大时间来进行排序
(
select 名称,最大时间=max(time1) from
(
select 名称,time1 from tb
union all select 名称,time2 from tb
union all select 名称,time3 from tb
union all select 名称,time4 from tb
union all select 名称,time5 from tb
union all select 名称,time6 from tb
) a
group by 名称
) b
order by 最大时间 desc