create table ndd987 
(
 id1 varchar(10),
 id2 varchar(10),
 id3 varchar(10),
 id101 varchar(10),
 id102 varchar(10)
)
   
insert into ndd987
select 'aa','bb','cc','dd','ee' union all 
select 'aa','','cc','dd','ee'union all 
select 'aa','bb','','dd','ee'union all 
select 'aa','bb','cc','dd',''union all 
select 'aa','bb','cc','dd','ee'


select * from ndd987



select case  when id1 = '' then  '987' else  id1 end+
         case  when id2 = '' then  '987' else  id2 end+
         case when id3 = '' then  '987' else  id3 end as 数据,
 id101,id102 from ndd987

=============================
数据     字段101       字段102 

aabbcc    dd    ee
aa987cc    dd    ee
aabb987    dd    ee
aabbcc    dd    
aabbcc    dd    ee