最近，在论坛中，遇到了不少比较难的sql问题，虽然自己都能解决，但发现过几天后，就记不起来了，也忘记解决的方法了。
所以，觉得有必要记录下来，这样以后再次碰到这类问题，也能从中获取解答的思路。另外，考虑到前2篇太长，看起来不太方便，所以拆分为第3篇
1、分组查询问题
http://bbs.csdn.net/topics/390619682?page=1#post-395835328
例子表结构数据如下：
id status date price
1 1 2013-10-01 218
2 1 2013-10-02 218
3 0 2013-10-03 218
4 0 2013-10-04 238
5 0 2013-10-05 238
6 0 2013-10-06 238
7 0 2013-10-07 258
8 0 2013-10-08 258
9 0 2013-10-09 218
想获取的结果集一：
2013-10-01至2013-10-03 218
2013-10-04至2013-10-06 238
2013-10-07至2013-10-08 258
2013-10-09至2013-10-09 218
想获取的结果集二：
1 2013-10-01至2013-10-02 218
0 2013-10-03至2013-10-03 218
0 2013-10-04至2013-10-06 238
0 2013-10-07至2013-10-08 258
0 2013-10-09至2013-10-09 218
我的解法：
--drop table tb
create table tb(id int,status int,date varchar(10),price int)
insert into tb
select 1, 1, '2013-10-01', 218 union all
select 2, 1, '2013-10-02', 218 union all
select 3, 0, '2013-10-03', 218 union all
select 4, 0, '2013-10-04', 238 union all
select 5, 0, '2013-10-05', 238 union all
select 6, 0, '2013-10-06', 238 union all
select 7, 0, '2013-10-07', 258 union all
select 8, 0, '2013-10-08', 258 union all
select 9, 0, '2013-10-09', 218 --union all
--select 10, 0, '2013-10-10', 218
go
--第一个结果集
;with t
as
(
select *,
row_number() over(partition by price order by id) as rownum,
min(id) over(partition by price) as min_id
from tb
),
tt
as
(
select id,
price,
a.date,
rownum - (id - min_id) as interval
from t a
)
select min(date) + '至' + max(date) as date,
price
from tt
group by price,interval
order by 1
/*
date price
2013-10-01至2013-10-03 218
2013-10-04至2013-10-06 238
2013-10-07至2013-10-08 258
2013-10-09至2013-10-09 218
*/
--第2个结果集
;with t
as
(
select *,
row_number() over(partition by status,price order by id) as rownum,
min(id) over(partition by status,price) as min_id
from tb
),
tt
as
(
select id,
price,
a.date,
a.status,
rownum - (id - min_id) as interval
from t a
)
select status,min(date) + '至' + max(date),price
from tt
group by status,price,interval
order by 2
/*
status date price
1 2013-10-01至2013-10-02 218
0 2013-10-03至2013-10-03 218
0 2013-10-04至2013-10-06 238
0 2013-10-07至2013-10-08 258
0 2013-10-09至2013-10-09 218
*/
2、MS-SQL 根据实际所需规格table去比对另一个库存table取浪费最少的数据
http://bbs.csdn.net/topics/390619048
情境描述：根据表A里的物料去比对表B,然后表A根据A1括号里两个尺寸浪费最少来将A1替换成最省的物料。
表A用量需求表：Table A
A0(自增长ID) A1(物料编号)
-------------------------------
0 ls001-(900*110)
1 ls002-(200*300)
....
表B库存物料表: B1没有重复，可以当作ID来使用 Table B:
B1(库存物料) B2(规格1) B3（规格2）
----------------------------------------------
ls001-(700*200) 700 200
ls001-(910*140) 910 140
ls001-(920*120) 920 120
... ... ...
ls002-(100*200) 100 200
ls002-(200*350) 200 350
ls002-(220*320) 220 320
...
原理是：ls001取(920*120)的话浪费分别是左边920-900=20，右边120-110=10，总共浪费是30， 是ls001库存规格(700*200)，(910*140)，(920*120)里浪费最少的，ls002同理。
最后A1字段被替换后的效果如下：
A0(自增长ID) A1(物料编号)
-------------------------------
0 ls001-(920*120)
1 ls002-(220*320)
...
各位有什么好的方案或者算法可分享来学习借鉴一下 ^_^
我的解法：
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)
*/
3、查询出一段数据后判断记录里面的最大id,是否大于值a 查询语句如下：
http://bbs.csdn.net/topics/390619191
select top 200 id, ClassId,Name,Price,BoxContain,BoxLength,BoxWidth,BoxHeight,CName,EName,CPack,PhotoFolder,EPack,0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08 from ProductData where ClassId=101 and BoxContain >0 and BoxContain is not null and round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3) >=0 And round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3) <= 10000 and (0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08) >=10 and (0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08) <=1000 and EPack='Window Box' order by id asc
我的解法，适用于SQL Server 2000：
select *
from
(
select top 200 id, ClassId,Name,Price,BoxContain,BoxLength,BoxWidth,BoxHeight,CName,EName,CPack,PhotoFolder,EPack,
0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08
from ProductData
where ClassId=101 and BoxContain >0 and BoxContain is not null
and round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3) >=0
And round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3) <= 10000
and (0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08) >=10
and (0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08) <=1000
and EPack='Window Box'
order by id asc
)t
where
(
select max(id)
from
(
select top 200 id, ClassId,Name,Price,BoxContain,BoxLength,BoxWidth,BoxHeight,CName,EName,CPack,PhotoFolder,EPack,
0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08
from ProductData
where ClassId=101 and BoxContain >0 and BoxContain is not null
and round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3) >=0
And round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3) <= 10000
and (0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08) >=10
and (0.46*(round(((convert(decimal(10,2),BoxLength)*convert(decimal(10,2),BoxWidth) * convert(decimal(10,2),BoxHeight))/1000000),3))*35.32/BoxContain+Price/6*1.08) <=1000
and EPack='Window Box'
order by id asc
)t
) > a