SQL SEVER 怎么取三列数据的最大者
inf2232_pay1   , inf2234_pay3  , inf2235_pay4   code 
10                20               30            001
100                60               80           002 
20                90                 10          003
将inf2232_pay1   , inf2234_pay3  , inf2235_pay4  比较后得出其最大值，如下结果

inf2232_pay1   , inf2234_pay3  , inf2235_pay4   code 
0                 0                30            001
100               0                0             002 
0                 90               0             003

------解决方案--------------------
case when
------解决方案--------------------

create table af

(inf2232_pay1 int,inf2234_pay3 int,inf2235_pay4 int,code varchar(10))



insert into af

 select 10,20,30,'001' union all

 select 100,60,80,'002' union all

 select 20,90,10,'003'





update af

 set inf2232_pay1=case when inf2232_pay1>inf2234_pay3 and inf2232_pay1>inf2235_pay4

                       then inf2232_pay1 else 0 end,

     inf2234_pay3=case when inf2234_pay3>inf2232_pay1 and inf2234_pay3>inf2235_pay4

                       then inf2234_pay3 else 0 end,

     inf2235_pay4=case when inf2235_pay4>inf2232_pay1 and inf2235_pay4>inf2234_pay3

                       then inf2235_pay4 else&