ÕâÑùµÄSqlÈçºÎд? - MS-SQL Server / »ù´¡Àà

SQL code:

ÓÐÈý¸ö±í£¬ÒµÎñ±í(Business),±¨Ãû±í(learn),¿ÆÄ¿±í(subject)
Create table Business
(
id varchar(50) primary key,
bName varchar(100)--ÒµÎñÃû
)
insert Business
select 1,'µÚÒ»¸öÒµÎñ' union
select 2,'µÚ¶þ¸öÒµÎñ'
---------
Create Table Subject
(
id int identity primary key,
name varchar(100)--¿ÆÄ¿
)
insert subject (name)
select 'ÓïÎÄ' union
select 'Êýѧ' union
select 'Ó¢Óï' union
select '»¯Ñ§' union
select 'ÎïÀí'
---------------
Create Table learn --drop table learn
(
id int identity primary key,
bid varchar(50) foreign key references Business(id),
name varchar(50),--±¨ÃûÈË
subjectList varchar(100),--±¨ÃûÈËËùÑ¡¿ÆÄ¿£¬¼Ç¼ÒÔ,¸ô¿ªµÄ¿ÆÄ¿±íid
)
insert learn(bid,name,subjectList)
select 1,'ÕÅÈý','1,3,4' union
select 1,'ÀîËÄ','2,3' union
select 1,'ÍõÎå','4,5' union
select 2,'ÂíÁù','1,2'
--------------

ÇóÒ»±ÊÒµÎñµÄ±¨ÃûÈ˼Ǽ: ÈçµÚÒ»±ÊÒµÎñµÄ±¨ÃûÈ˼ǼӦΪ:
id bid name subjectLsit
1 1 ÀîËÄ Êýѧ,Ó¢Óï
2 1 ÍõÎå »¯Ñ§,ÎïÀí
3 1 ÕÅÈý ÓïÎÄ,Ó¢Óï,»¯Ñ§


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CREATE FUNCTION dbo.f_strUnite(@subjectList varchar(100)) 
RETURNS varchar(100) 
AS 
BEGIN 
DECLARE