SQL中，源表里ID和序号相同的记录，只要项目编号有A值，那么项目编号为其他值的记录不显示。

按ID和序号分组，项目编号为A值，则有其他值的记录不显示；若项目编号中无A值的话，则全部显示。

看看

select t1.id,t1.xh,t1.xmbh from (select t.id,t.xh,t.xmbh,row_number() over (partition by t.id order by t.xmbh) as list from t )t1
where t1.xmbh='A' and t1.list =1
union all
select * from t where id not in (select id from t where xmbh='A')