Sql Server2005¶Ôt sqlµÄÔöÇ¿Ö®Cross Apply

Cross Applyʹ±í¿ÉÒԺͱíÖµº¯Êý½á¹û½øÐÐjoin£¬ÔÚÏÂÃæµÄʾÀýÖн¨ÁËÁ½¸ö±íºÍÒ»¸ö±íÖµº¯Êý£¬T_bµÄÁÐa_idsÖлá´æ·Åa±íµÄidÓÃ,·Ö¸îµÄ×Ö·û´®Á¬½Ó£»ÎÒÃÇͨ¹ýcross applyʹT_a£¬T_b±íͨ¹ýsplitIDs inner join Á¬½Ó¡£Ç뿴ʾÀý£ºGO
if object_id('T_a','U') is not null
drop table T_a
GO
CREATE TABLE T_a(    id int unique not null,
    name varchar(50),
)
GO
if object_id('T_b',N'U') is not null
drop table T_b
GO
create table T_b
(
    id int unique not null,
    name varchar(10),
    a_ids varchar(100) null --ÒªÔÚÕâÒ»ÁÐÖдæ·Åt_a±íµÄIDÐòÁÐ,ÕâÑù×öÁ¬µÚÒ»·¶Ê½¶¼Ã»ÓÐÂú×㣬µ«ÊÇÓÐʱºò¿¼ÂÇÐÔÄÜ»òÉè¼ÆÎÒÃÇ¿ÉÄÜ»áÏñÕâôÓÃ
)
GO
--³õʼ»¯Êý¾Ý
INSERT INTO T_a VALUES(1,'A-1')
INSERT INTO T_a VALUES(2,'A-2')
INSERT INTO T_a VALUES(3,'A-3')
INSERT INTO T_a VALUES(4,'A-4')
INSERT INTO T_a VALUES(5,'A-5')
INSERT INTO T_b VALUES(1,'B-1','1,2,4')
GO
--´´½¨Ò»¸ö±íÖµº¯Êý£¬ÓÃÀ´²ð·ÖÓöººÅ·Ö¸îµÄÊý×Ö´®£¬·µ»ØÖ»ÓÐÒ»ÁÐÊý×ֵıí
if object_id('splitIDs','TF') is not null
drop function splitIDs;
GO
create function splitIDs(
    @Ids nvarchar(1000)
)
returns @t_id TABLE (id bigint)
as
begin
    declare @i int,@j int,@l int,@v bigint;
    set @i = 0;
    set @j = 0;
    set @l = len(@Ids);
    while(@j < @l)
    begin
       set @j = charindex(',',@Ids,@i+1);
       if(@j = 0) set @j = @l+1;
       set @v = cast(SUBSTRING(@Ids,@i+1,@j-@i-1) as bigint);
       INSERT INTO @t_id VALUES(@v)
       set @i = @j;
    end
    return;
end
GO
--²âÊÔsplitIDsµÄÖ´ÐÐЧ¹û
select * from splitIDs('1,2,4,3')
select * from splitIDs('100')
select * from splitIDs(NULL)
GO
--ʹÓÃcross apply»ñµÃt_b±íÖÐÖ¸¶¨ÐжÔÓ¦µÄËùÓÐt_a±íÖеļǼ
select