求条语句,该如何解决

求条语句
表:a
字段:id,cname


declare   @id   int
while(类似select   @id   =   id   from   a   where   cname   = 'xxx ')
begin
select   *   from   a   where   id   =@   id
end


----

while里的语句要求判断是否有满足条件的id存在,不存在就不进入while循环,如果存在则给@id赋值,并进入循环.

while结构不可改变(do...while)不在考虑之列.




[解决办法]
while exists (select * from a where cname= 'xxx ')