例如我有下表
+--------+-----------------------+--+
| Id | BuyingAttribute | |
+--------+-----------------------+--+
| 1 | Low Price | |
| 1 | Good Communication | |
| 1 | English Speaker | |
| 2 | Low Price | |
| ...etc | ...etc | |
+--------+-----------------------+--+
有没有办法可以自动将所有值传输到是/否值。我知道我可以像这样使用案例陈述
SELECT
Id,
CASE WHEN BuyingAttribute = 'Low Price' THEN True ELSE False END AS Buying Attribute
FROM
myTable
但是，是否存在自动化方法，因为如果我有50个值并编写50个case语句来生成如下结果，则会非常耗时
+----+-----------------------+---------------+-------------------------+----------------------+
| Id | BuyingAttribute | BA(Low Price) | BA(Good Communication) | BA(English Speaker) |
+----+-----------------------+---------------+-------------------------+----------------------+
| 1 | Low Price | True | False | False |
| 1 | Good Communication | False | True | False |
| 1 | English Speaker | False | False | True |
| 2 | Low Price | True | False | False |
| | | | | |
+----+-----------------------+---------------+-------------------------+----------------------+
答案 0 :(得分：0)
Create table #tmp (Id int, BuyingAttribute VARCHAR(30))
insert into #tmp values(1,'Low Price')
insert into #tmp values(1,'Good Communication')
insert into #tmp values(1,'English Speaker')
insert into #tmp values(2,'Low Price')
SELECT * FROM #tmp
SELECT * ,
CASE BuyingAttribute WHEN 'Low Price' THEN 'True' ELSE 'False' END [BA(Low Price)],
CASE BuyingAttribute WHEN 'Good Communication' THEN 'True' ELSE 'False' END [BA(Good Communication)],
CASE BuyingAttribute WHEN 'English Speaker' THEN 'True' ELSE 'False' END [BA(English Speaker)]
FROM #tmp
Drop table #tmp
答案 1 :(得分：0)
您可以通过将所有可能的购买属性分配给所有ID来实现此目的
select tid,row_number() over (partition by tid order by baba) rn,
baba,
t.BuyingAttribute tba
from
(
select distinct t.id tid, ba.buyingattribute baba from t
cross join (select distinct t.BuyingAttribute from t) ba
) s
left join t on t.BuyingAttribute = s.baba and t.id = s.tid
结果
tid rn baba tba
----------- -------------------- ------------------------------ ------------------------------
1 1 English Speaker English Speaker
1 2 Good Communication Good Communication
1 3 Low Price Low Price
2 1 English Speaker NULL
2 2 Good Communication NULL
2 3 Low Price Low Price
然后我们可以将它包装在一个轴
中select tid,rn,
case when [English Speaker] is not null then 'true' else 'false' end as 'English Speaker',
case when [Good Communication] is not null then 'true' else 'false' end as 'Good Communication',
case when [Low Price] is not null then 'true' else 'false' end as 'Low Price'
from
(
select tid,row_number() over (partition by tid order by baba) rn,
baba,
t.BuyingAttribute tba
from
(
select distinct t.id tid, ba.buyingattribute baba from t
cross join (select distinct t.BuyingAttribute from t) ba
) s
left join t on t.BuyingAttribute = s.baba and t.id = s.tid
--order by tid, baba
) t
pivot (max(baba) for baba in ([English Speaker],[Good Communication],[Low Price])) pvt
order by tid,rn
获取
tid rn English Speaker Good Communication Low Price
----------- -------------------- --------------- ------------------ ---------
1 1 true false false
1 2 false true false
1 3 false false true
2 1 true false false
2 2 false true false
2 3 false false true
这对你来说是一个问题，因为你不知道你有多少购买属性，所以我们需要构建上述语句并执行动态sql。
declare @s1 nvarchar(max)
declare @s10 varchar(max)
declare @s9 varchar(max)
set @s1 = 'select tid,rn,'
set @s9 = (
select top 1 STUFF((
SELECT 'case when [' + t1.buyingattribute + '] is not null then ' + char(39) + 'true' + char(39) +
' else ' + char(39) + 'false' + char(39) + ' end as ' + char(39) + t1.buyingattribute + char(39) + ','
from t t1 where t1.buyingattribute >= t.buyingattribute
FOR XML PATH(''), TYPE).value('.', 'nVARCHAR(max)'), 1, 1, '')
from
(select distinct buyingattribute from t) t
)
--select substring(@s9,patindex('%,%',@s9)+ 1, len(@s9) - patindex('%,%',@s9))
--select @s9
set @s9 = substring(@s9,1,len(@s9) -1)
set @s1 = concat(@s1,substring(@s9,patindex('%,%',@s9)+ 1, len(@s9) - patindex('%,%',@s9)))
set @s10 = ' from
(
select tid,row_number() over (partition by tid order by baba) rn,
baba,
t.BuyingAttribute tba
from
(
select distinct t.id tid, ba.buyingattribute baba from t
cross join (select distinct t.BuyingAttribute from t) ba
) s
left join t on t.BuyingAttribute = s.baba and t.id = s.tid
--order by tid, baba
) t
pivot (max(baba) for baba in ('
set @s9 = (
select top 1 STUFF((
SELECT '[' + t1.buyingattribute + '] ,'
from t t1 where t1.buyingattribute >= t.buyingattribute
FOR XML PATH(''), TYPE).value('.', 'nVARCHAR(max)'), 1, 1, '')
from
(select distinct buyingattribute from t) t
)
set @s9 = substring(@s9,1,len(@s9) - 1)
set @s1 = concat(@s1,@s10,substring(@s9,patindex('%,%',@s9)+ 1, len(@s9) - patindex('%,%',@s9)),' )) pvt order by tid,rn')
exec sp_executesql @s1