T-SQL build temporary tables, processing strings

Temporary table | string declare @str1 varchar (MB), @str2 varchar (m), @str3 varchar (MB), @str varchar (500)
Set @str1 = ' AADA,BBBF,CCC, '
Set @str2 = ' DDD,AAAAAA,FDSA '
Set @str3 = ' vvvvvv,aaabbbb '
Set @str = ' Fds,bbbf,eee,ddd,fff,hhhfg,dddde '
Right now:
Split the @str1 into AADA,BBBF,CCC three elements, where BBBF appeared in @str.
Split the @str2 into DDD,AAAAAA,FDSA three elements, in which DDD also appeared in @str.
Split the @str3 into VVVVVV,AAABBBB two elements, but no elements appeared in @str.
How can I use the program to achieve such a result
Actually, the real problem is this.
I have a data table with a field in it ClassID
One of the records of the data, such as: AADA,BBBF,CCC
Now to get such a result set, the ClassID will be split in accordance with the above split, the data obtained, in the @str (@str is a parameter from the outside) find out, how can I do?
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DECLARE @str varchar (500)

Set @str = ' Fds,bbbf,eee,ddd,fff,hhhfg,dddde '

CREATE table your table (ClassID varchar (100))
Insert your table values (' AADA,BBBF,CCC ')
Insert your table values (' DDD,AAAAAA,FDSA ')
Insert your table values (' VVVVVV,AAABBBB ')

CREATE TABLE #临时表 (a varchar (100))
DECLARE @aaa varchar (8000)
Set @aaa = ' Insert #临时表 SELECT * FROM (SELECT ' "' (@str, ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ') + ' "" "A"
EXEC (@aaa)

SELECT * from your table where exists (select 1 from #临时表 where ', ' + your table. classid+ ', ' like '%, ' +a+ ',% ')
Go

drop table your table, #临时表
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CREATE TABLE #t (
ID varchar (10))
DECLARE @str varchar (300)
Set @str = ' Fds,bbbf,eee,ddd,fff,hhhfg,dddde '
DECLARE @i int
DECLARE @len int
Set @i = 1
Set @str = ' Fds,bbbf,eee,ddd,fff,hhhfg,dddde ' + ', '
While @i < Len (@str)
Begin
Insert #t Select substring (@str, @i,charindex (",", @str, @i)-@i)
Set @i = charindex (', ', @str, @i) +1
End
SELECT * FROM datasheet A, #t B where CHARINDEX (b.id, A.classid) > 0


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CREATE TABLE T (ClassID varchar (100))
Insert T values (' AADA,BBBF,CCC ')
Insert T values (' DDD,AAAAAA,FDSA ')
Insert T values (' VVVVVV,AAABBBB ')




DECLARE @str varchar (500)

Set @str = ' Fds,bbbf,eee,ddd,fff,hhhfg,dddde '

Select top Identity (int,1,1) as ID into #t from sysobjects

Select distinct a.* from T A,
(Select substring (', ' +string+ ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', ', id+1)-id-1) As String
From (select @str As String) B, #t C
where substring (', ' +string+ ', ', ', id,8000) like ', _% ') D
where CHARINDEX (', ' +string+ ', ', ', ', ', ', ', ', ' ' +classid+ ', ', ') >0

drop table #t

Put the #t into a fixed table, faster.