[英]SQL Get closest value to a number
我需要从 Quantity 列中找到 Divide 列中每个数字的最接近的值,并将在这两个 Quantities 的 Value 列中找到的值。
示例:在 Divide 列中,5166 的值将最接近 Quantity 列的值 5000。为了避免多次使用这两个值,我需要将 5000 的值放在两个数字的值列中,如下例所示。 另外,是否可以在没有循环的情况下执行此操作?
Quantity Divide Rank Value
15500 5166 5 5000
1250 416 5 0
5000 1666 5 5000
12500 4166 4 0
164250 54750 3 0
5250 1750 3 0
6250 2083 3 0
12250 4083 3 0
1750 583 2 0
17000 5666 2 0
2500 833 2 0
11500 3833 2 0
1250 416 1 0
这里有几个答案,但它们都使用 ctes/complex 子查询。 有一种更简单/更快的方法,只需进行几次自我加入和分组
https://www.db-fiddle.com/f/rM268EYMWuK7yQT3gwSbGE/0
select
min(min.quantity) as minQuantityOverDivide
, t1.divide
, max(max.quantity) as maxQuantityUnderDivide
, case
when
(abs(t1.divide - coalesce(min(min.quantity),0))
<
abs(t1.divide - coalesce(max(max.quantity),0)))
then max(max.quantity)
else min(min.quantity) end as cloestQuantity
from t1
left join (select quantity from t1) min on min.quantity >= t1.divide
left join (select quantity from t1) max on max.quantity < t1.divide
group by
t1.divide
如果我理解要求, 5166
并不最接近5000
- 它接近5250
( 166
与84
的增量)
相应的查询,没有循环,应该是(这里的小提琴: https://dbfiddle.uk/?rdbms=sqlserver_2017&fiddle=be434e67ba73addba119894a98657f17 )。
(我添加了一个Value_Rank
,因为不确定您是否希望保留或重新计算Rank
)
select
Quantity, Divide, Rank, Value,
dense_rank() over(order by Value) as Value_Rank
from
(
select
Quantity, Divide, Rank,
--
case
when abs(Quantity_let_delta) < abs(Quantity_get_delta) then Divide + Quantity_let_delta
else Divide + Quantity_get_delta
end as Value
from
(
select
so.Quantity, so.Divide, so.Rank,
-- There is no LessEqualThan, assume GreaterEqualThan
max(isnull(so_let.Quantity, so_get.Quantity)) - so.Divide as Quantity_let_delta,
-- There is no GreaterEqualThan, assume LessEqualThan
min(isnull(so_get.Quantity, so_let.Quantity)) - so.Divide as Quantity_get_delta
from
SO so
left outer join SO so_let
on so_let.Quantity <= so.Divide
--
left outer join SO so_get
on so_get.Quantity >= so.Divide
group by so.Quantity, so.Divide, so.Rank
) so
) result
或者,如果最接近你的意思是以前最接近的(这里的小提琴: https://dbfiddle.uk/?rdbms=sqlserver_2017&fiddle=b41fb1a3fc11039c7f82926f8816e270 )。
select
Quantity, Divide, Rank, Value,
dense_rank() over(order by Value) as Value_Rank
from
(
select
so.Quantity, so.Divide, so.Rank,
-- There is no LessEqualThan, assume 0
max(isnull(so_let.Quantity, 0)) as Value
from
SO so
left outer join SO so_let
on so_let.Quantity <= so.Divide
group by so.Quantity, so.Divide, so.Rank
) result
您不需要循环,基本上您需要找到除数和所有数量(第一个 cte)之间的最小差异。 然后用这个距离找到对应的记录(第二个cte)然后和你的初始表join得到转换后的值(最终选择)
;with cte as (
select t.Divide, min(abs(t2.Quantity-t.Divide)) as ClosestQuantity
from #t1 as t
cross apply #t1 as t2
group by t.Divide
)
,cte2 as (
select distinct
t.Divide, t2.Quantity
from #t1 as t
cross apply #t1 as t2
where abs(t2.Quantity-t.Divide) = (select ClosestQuantity from cte as c where c.Divide = t.Divide)
)
select t.Quantity, cte2.Quantity as Divide, t.Rank, t.Value
from #t1 as t
left outer join cte2 on t.Divide = cte2.Divide
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