2.
CREATE FUNCTION isC (@UserID varchar(30))
RETURNS int
AS
declare @c1 int,@c2 int
select @c1=count(distinct 登陆号) from RB where 借书证号= @userid or 借书证号 = '14002'
select @c2=count(distinct 登陆号) from RB where 借书证号 = '14002'
2.
select t1.借书证号 from (select count(*) as num,k.借书证号 from (select a.* from R-B a inner join (select 登陆号 from R-B where 借书证号=14002) b on a.登陆号=b.登陆号) k group by k.借书证号) t1 inner join ( select count(*) as num from R-B where 借书证号=14002) t2 on t1.num=t2.num