求一sql

2010-04-06 11:32:56 104 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

基于SQL求集合的交、并、补对数据库查询结果集求补（差）、交、并集，可利用SQL的EXCEPT（补集）、INTERSECT（交集）和UNION（并集）关键词，其中Mysql仅支持UNION，但可以利用SQL实现EXCEPT、INTERSECT的功能。阅读详情







DECLARE  @T TABLE

(

	Air NVARCHAR(30),

	NameT NVARCHAR(100)

)



INSERT INTO @T

select 'UA,NW,CX,TD','IAM1' 

UNION ALL

select 'UA,NW,LH,TD','IAM2'





select * from @T



根据Air拆分，想得到如下数据:





UA,IAM1

NW,IAM1

CX,IAM1

TD,IAM1

UA,IAM2

NW,IAM2

LH,IAM2

TD,IAM2

...全文

sql复杂场景：求连续在线天数有一张在线日志表，记录了用户每天是否在线的情况，求最近连续在线天数及最长连续在线天数。数据如下： user_id date is_online 11 2022/1/1 1 11 2022/1/2 1 11 2022/1/3 1 11 2022/1/4 0 11 2022/1/5 0 11 2022/1/6 1 12 2022/2/3 1 12 2022/2/4 1 阅读详情

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老黎 2010-04-06

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DECLARE  @T TABLE

(

    Air NVARCHAR(30),

    NameT NVARCHAR(100)

)



INSERT INTO @T

select 'UA,NW,CX,TD','IAM1' 

UNION ALL

select 'UA,NW,LH,TD','IAM2'



select air = substring(air,b.number,charindex(',',air+',',charindex(',',a.air+',',b.number))-b.number)

       ,NameT

from @T a

     inner join master..spt_values b

on charindex(',',','+a.air,b.number) = b.number 

and type = 'P'



--结果

/*

air                            NameT

------------------------------ ----------------------------------------------------------------------------------------------------

UA                             IAM1

NW                             IAM1

CX                             IAM1

TD                             IAM1

UA                             IAM2

NW                             IAM2

LH                             IAM2

TD                             IAM2



(8 行受影响)

*/

htl258_Tony 2010-04-06

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DECLARE  @T TABLE

(

    Air NVARCHAR(30),

    NameT NVARCHAR(100)

)



INSERT INTO @T

select 'UA,NW,CX,TD','IAM1' 

UNION ALL

select 'UA,NW,LH,TD','IAM2'





select a.NameT, b.Air  

from   

(   

   select NameT, Air = convert(xml,'<v>' + replace(Air, ',', '</v><v>') + '</v>') from @t   

) a   

outer apply   

(   

   select Air = n.v.value('.', 'varchar(10)') from a.Air.nodes('/v') n(v)   

) b   

/*

NameT	Air

IAM1	UA

IAM1	NW

IAM1	CX

IAM1	TD

IAM2	UA

IAM2	NW

IAM2	LH

IAM2	TD

*/

--小F-- 2010-04-06

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--参考

拆分表:



--> --> (Roy)生成測試數據

 

if not object_id('Tab') is null

    drop table Tab

Go

Create table Tab([Col1] int,[COl2] nvarchar(5))

Insert Tab

select 1,N'a,b,c' union all

select 2,N'd,e' union all

select 3,N'f'

Go



--SQL2000用辅助表:

if object_id('Tempdb..#Num') is not null

    drop table #Num

go

select top 100 ID=Identity(int,1,1) into #Num from syscolumns a,syscolumns b

Select 

    a.Col1,COl2=substring(a.Col2,b.ID,charindex(',',a.Col2+',',b.ID)-b.ID) 

from 

    Tab a,#Num b

where

    charindex(',',','+a.Col2,b.ID)=b.ID --也可用 substring(','+a.COl2,b.ID,1)=','

--2000不使用辅助表

Select

    a.Col1,COl2=substring(a.Col2,b.number,charindex(',',a.Col2+',',b.number)-b.number) 

from 

    Tab a join master..spt_values  b 

    ON B.type='p' AND B.number BETWEEN 1 AND LEN(A.col2)

where

     substring(','+a.COl2,b.number,1)=','





SQL2005用Xml:



select 

    a.COl1,b.Col2

from 

    (select Col1,COl2=convert(xml,'<root><v>'+replace(COl2,',','</v><v>')+'</v></root>') from Tab)a

outer apply

    (select Col2=C.v.value('.','nvarchar(100)') from a.COl2.nodes('/root/v')C(v))b









SQL05用CTE:



;with roy as 

(select Col1,COl2=cast(left(Col2,charindex(',',Col2+',')-1) as nvarchar(100)),Split=cast(stuff(COl2+',',1,charindex(',',Col2+','),'') as nvarchar(100)) from Tab

union all

select Col1,COl2=cast(left(Split,charindex(',',Split)-1) as nvarchar(100)),Split= cast(stuff(Split,1,charindex(',',Split),'') as nvarchar(100)) from Roy where split>''

)

select COl1,COl2 from roy order by COl1 option (MAXRECURSION 0)



生成结果:

/*

Col1        COl2

----------- -----

1           a

1           b

1           c

2           d

2           e

3           f

*/

让你望见影子的墙 2010-04-06

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select parsename(Air,1),NameT from @t union all
select parsename(Air,2),NameT from @t union all
select parsename(Air,3),NameT from @t union all
select parsename(Air,4),NameT from @t

SQL77 2010-04-06

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拆分函数一大堆,参考ROY大哥博客,

如果是4个分段,考虑用PARSENAME函数

求一sql

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