select (case when c=0 then a else b end) as val from table
create table tablename( a char(10), b char(10), c int )insert into tablename select 'aa','bb',0 union all select 'cc','dd',1select tablename.*, value=case when c=0 then a else b end from tablename结果: a b c value aa bb 0 aa cc dd 1 dd
a char(10),
b char(10),
c int )insert into tablename
select 'aa','bb',0
union all
select 'cc','dd',1select tablename.*, value=case when c=0 then a else b end from tablename结果:
a b c value
aa bb 0 aa
cc dd 1 dd