求sql语句 - MS-SQL Server / 基础类

两个表 B 表的fd_person_id 与A表中的fd_id关联如下
A表
fd_id name  
1 a
2 b
3 c
B表
fd_id fd_person_id  
1 1
2 2

现在要判断 给定一个 A表的 NAME 判断这个name 是否存在与A表中又不存在于B表中
比如 给name 为c 返回的count 为1 给a b d e 等都返回0
谢谢

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SQL code:
select * from a where not exists (select 1 from b where a.fd_id=b.fd_id)

and a.name='c'

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SQL code:
select count(1) as cnt from b where exists(select 1 from a where a.fd_id= b.fd_person_id and name='c')

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SQL code:
select name,num=count(*)
from A left join B on A.fd_id=B.fd_person_id
where B.fd_id is null and name='c'
group by name

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ths