sql problem more difficult to appear in the forum: 30 (row_number function material combinations issue)

Original: SQL problem more difficult to appear in the forum: 30 (row_number function material combinations issue)

In the forum, I met a lot more difficult sql problem, although they can be resolved, but found a few days later, they can not remember, forget the solution of.

So, I feel the need to be recorded, so that after the encounter this problem again, and get answers from the idea.

MS-SQL table based on the actual inventory required specification data table to take minimal waste other than

http://bbs.csdn.net/topics/390619048

Context description: Table A material according to comparison tables B, Table A and A1 happened to be replaced according to the material of least two dimensions A1 brackets waste.


Table A table amount of demand: the Table A


A0 (self-growth ID) A1 (item number)   
-------------------------------
ls001- 0 (900 * 110)
. 1 ls002- (200 is 300 *)
....


table B table Stock material: B1 does not repeat, can be used as ID B the table:

Bl (stock material) B2 (size 1) B3 (size 2)
----------------------------------------------
ls001- (200 is 700 *) 700 200 is
ls001- (910 * 140) 910 140
ls001- (920. * 120) 920. 120
... ... ...
ls002- (200 is 100 *) 100 200 is
ls002- (* 200 is 350) 350 200 is
ls002- (220 * 320.) 320. 220
...              
 
The principle is: ls001 taken (920 120 *) are left, then waste 920-900 = 20, 120-110 = 10 to the right, a total of 30 to waste, is LS001 stock standard (700 * 200), (910 * 140), ( 920 * 120) in a minimum of waste, ls002 empathy.

Finally, the effect of the field A1 is replaced by the following:

A0 (from growth ID) A1 (item number)   
----------------------------- -
0 ls001- (920 * 120)
1 ls002- (220 * 320)
...

you have any good program or algorithm can learn to share what ^ _ ^

My solution:

   
   
drop table a
drop table b

create table a (a0 int,a1 varchar( 100),a2 int,a3 int)

insert into a
SELECT 0, 'ls001-(900*110)', 900, 110 UNION ALL
SELECT 1, 'ls002-(200*300)', 200, 300


create table b (B1 varchar( 100),B2 int,B3 int)

insert into b
SELECT 'ls001-(700*200)', 700, 200 UNION ALL
SELECT 'ls001-(910*140)', 910, 140 UNION ALL
SELECT 'ls001-(920*120)', 920, 120 UNION ALL
SELECT 'ls002-(100*200)', 100, 200 UNION ALL
SELECT 'ls002-(200*350)', 200, 350 UNION ALL
SELECT 'ls002-(220*320)', 220, 320


;with t
as
(
select a0,a1,
substring(a1, 1, charindex( '-',a1) -1) as b1,
a2,a3
--substring(a1,charindex('(',a1)+1, charindex('*',a1)-charindex('(',a1)-1) as b2,
--substring(a1,charindex('*',a1)+1, charindex(')',a1)-charindex('*',a1)-1) as b3

from a
),

tt
as
(
select t.a0,
t.a1,
b.b1,
row_number() over( partition by t.a1
order by abs(t.a2-b.b2) + abs(t.a3 - b.b3)) as rownum
from b
inner join t
on b.b1 like t.b1 + '%'
)

select a0,b1 as a1
from tt
where rownum = 1
/*
a0 a1
0 ls001-(920*120)
1 ls002-(220*320)
*/