转换一句嵌套查询（转化为非嵌套）

--原数据
ID          Name                 Class
----------- -------------------- --------------------
1           草莓                   浆果类
2           葡萄                   浆果类
3           杏仁                   坚果类
4           榛子                   坚果类
5           花生                   坚果类

SELECT * 
FROM moral.t_Test
WHERE Class = (SELECT TOP 1 Class FROM moral.t_Test WHERE Name = '草莓')

--查询结果
ID          Name                 Class
----------- -------------------- --------------------
1           草莓                   浆果类
2           葡萄                   浆果类

create table tb(ID int, Name nvarchar(10), Class nvarchar(10))
insert into tb select 1,'草莓','浆果类'
insert into tb select 2,'葡萄','浆果类'
insert into tb select 3,'杏仁','坚果类'
insert into tb select 4,'榛子','坚果类'
insert into tb select 5,'花生','坚果类'
go
select a.* from tb a inner join tb b on a.Class=b.class where b.Name='草莓'
/*
ID          Name       Class
----------- ---------- ----------
1           草莓         浆果类
2           葡萄         浆果类

(2 行受影响)

*/
go
drop table tb

SELECT a.* 
FROM moral.t_Test as a,moral.t_Test  as b 
where a.Class=b.Class and b.Name=N'草莓'