CREATE TABLE exmp_test
(
id int,
v1 int,
v2 int,
v3 int,
v4 int
)
SELECT * FROM exmp_test
id v1 v2 v3 v4
1 2 4 6 7
1 4 77 3 8
I want to add the value of the [id] column to (whichever has least value for v1 ,v2 ,v3 ,v4) for each row.
我想为每一行添加[id]列的值(以v1,v2,v3,v4的最小值为准)。
As an example, for the first row, the [id] value should be add to v1 (because it has the lowest value). For the second row, the [id] value should be add to v3 (because it has the lowest value).
例如,对于第一行,[id]值应该添加到v1(因为它具有最低值)。对于第二行,[id]值应添加到v3(因为它具有最低值)。
How would I write the SQL to do this?
如何编写SQL来执行此操作?
2 个解决方案
#1
2
You could normalize the table in a CTE (common table expression), and then select the row with the minimum value. Based on the comment below your question, I've added priority for v1.
您可以在CTE(公用表表达式)中规范化表,然后选择具有最小值的行。根据您的问题下面的评论,我已经为v1添加了优先级。
;with Normal as (
select id, v1 as value, 1 as prio from YourTable
union all select id, v2, 2 as prio from YourTable
union all select id, v3, 3 as prio from YourTable
union all select id, v4, 4 as prio from YourTable
)
select top 1 id, value
from Normal
where value = (
select min(value) from Normal
)
order by prio
After re-reading your question, here's a way to look at the lowest value per row and add the id
field to that:
在重新阅读您的问题之后,这里有一种方法可以查看每行的最低值并将id字段添加到:
update t1
set v1 = v1 + case when mincol = 1 then id else 0 end
, v2 = v2 + case when mincol = 2 then id else 0 end
, v3 = v3 + case when mincol = 3 then id else 0 end
, v4 = v4 + case when mincol = 4 then id else 0 end
from (
select id, v1, v2, v3, v4,
case
when v1 <= v2 and v1 <= v3 and v1 <= v4 then 1
when v2 <= v3 and v2 <= v4 then 2
when v3 <= v4 then 3
else 4
end as mincol
from YourTable
) t1
#2
1
You can do the same using UVPIVOT
你可以使用UVPIVOT做同样的事情
Test data
declare @exmp_test table(id int, v1 int,v2 int,v3 int,v4 int)
insert into @exmp_test
select 1, 2 , 4 , 6, 7 union all
select 1 , 4 , 77 , 3 , 8 union all
select 2 , 4 , 16 , 1 , 8
Query
;with cte as(select row_number() over(order by id) as rn,t.v1 + t.v2 + t.v3 + t.v4 as sumallversions,t.* from @exmp_test t)
,unpvtcte as(select rn,id as versions,vals from (select rn,[v1],[v2],[v3],[v4] from cte)t
unpivot (vals for id in([v1],[v2],[v3],[v4]))as unpvt)
update @exmp_test
set id = y.sumall
from @exmp_test e
join (
select c.id,c.id + x.minvals as sumall,c.sumallversions, x.minvals from cte c
join(select rn,MIN(vals) minvals from unpvtcte group by rn)x on x.rn = c.rn) y
on y.id = e.id
and y.sumallversions = e.v1 + e.v2 + e.v3 + e.v4
Output:
id v1 v2 v3 v4
3 2 4 6 7
4 4 77 3 8
3 4 16 1 8
#1
2
You could normalize the table in a CTE (common table expression), and then select the row with the minimum value. Based on the comment below your question, I've added priority for v1.
您可以在CTE(公用表表达式)中规范化表,然后选择具有最小值的行。根据您的问题下面的评论,我已经为v1添加了优先级。
;with Normal as (
select id, v1 as value, 1 as prio from YourTable
union all select id, v2, 2 as prio from YourTable
union all select id, v3, 3 as prio from YourTable
union all select id, v4, 4 as prio from YourTable
)
select top 1 id, value
from Normal
where value = (
select min(value) from Normal
)
order by prio
After re-reading your question, here's a way to look at the lowest value per row and add the id
field to that:
在重新阅读您的问题之后,这里有一种方法可以查看每行的最低值并将id字段添加到:
update t1
set v1 = v1 + case when mincol = 1 then id else 0 end
, v2 = v2 + case when mincol = 2 then id else 0 end
, v3 = v3 + case when mincol = 3 then id else 0 end
, v4 = v4 + case when mincol = 4 then id else 0 end
from (
select id, v1, v2, v3, v4,
case
when v1 <= v2 and v1 <= v3 and v1 <= v4 then 1
when v2 <= v3 and v2 <= v4 then 2
when v3 <= v4 then 3
else 4
end as mincol
from YourTable
) t1
#2
1
You can do the same using UVPIVOT
你可以使用UVPIVOT做同样的事情
Test data
declare @exmp_test table(id int, v1 int,v2 int,v3 int,v4 int)
insert into @exmp_test
select 1, 2 , 4 , 6, 7 union all
select 1 , 4 , 77 , 3 , 8 union all
select 2 , 4 , 16 , 1 , 8
Query
;with cte as(select row_number() over(order by id) as rn,t.v1 + t.v2 + t.v3 + t.v4 as sumallversions,t.* from @exmp_test t)
,unpvtcte as(select rn,id as versions,vals from (select rn,[v1],[v2],[v3],[v4] from cte)t
unpivot (vals for id in([v1],[v2],[v3],[v4]))as unpvt)
update @exmp_test
set id = y.sumall
from @exmp_test e
join (
select c.id,c.id + x.minvals as sumall,c.sumallversions, x.minvals from cte c
join(select rn,MIN(vals) minvals from unpvtcte group by rn)x on x.rn = c.rn) y
on y.id = e.id
and y.sumallversions = e.v1 + e.v2 + e.v3 + e.v4
Output:
id v1 v2 v3 v4
3 2 4 6 7
4 4 77 3 8
3 4 16 1 8