在 SQL 中自行加入以更新 table

Question

我有以下 table:

Category	Qty	Orders	Level
Product			0
Part 1	2	4	1
Part 2	3	5	1
Part 1.1	4	6	2
Part 1.2	5	7	2

如何用数量和订单的总和（不包括级别 0 的数量和订单）更新上面 table 的 0 级行？

即

Category	Qty	Orders	Level
Product	14 (i.e. 2+3+4+5)	22 (i.e. 4+5+6+7)	0
Part 1	2	4	1
Part 2	3	5	1
Part 1.1	4	6	2
Part 1.2	5	7	2

Answer 1

您可以使用使用子查询或 CTE 的 Update 语句，但我认为实际上您的 table 没有任何 Id（例如一个 id link 所有这些部分* 到特定产品。无论如何，原样：

Update myTable
   set Qty = agg.Qty, Orders=agg.Orders 
from (Select Sum(Qty) Qty, Sum(Orders) Orders from myTable where level > 0) agg
where level=0;

DBFiddle demo

Answer 2

Update TableName
set     Qty = (select Sum(Qty) from TableName where Level<>0),
        Orders = (select Sum(Qty) from TableName where Level<>0 )
where Level = 0

Answer 3

UPDATE yourtablename set qty = 
(Select sum(qty) from yourtablename
Where level != 0),
orders = 
(Select sum(orders) from yourtablename
Where level != 0) 
where level = 0

在 SQL 中自行加入以更新 table

Self join to update table in SQL

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