不用max函数返回表中最大值或者最小值

返回Test表中字段num的最大值或者最小值（不用Max函数）, 近为了好玩。：）

 

--返回最大值

select distinct num from Test where num not in

( select lesser.num from Test as greater,Test as lesser

where lesser.num<greater.num)

 

--返回最小值

select distinct num from Test where num not in

( select greater.num from Test as greater,Test as lesser

where lesser.num<greater.num)

 

 

原因是以下SQL返回的结果集中，lesser.num中包括所有num除了最大值，greater.num中包括所有num除了最小值：

select lesser.num,greater.num

from Test as lesser, Test as greater

where lesser.num < greater.num;