SQL-Oracle：使用来自另一个表的值的总和更新表列-使用公共​​键列条件

Question

Good Evening Stackoverflow team/members

Oracle version: 11g Release 11.1.0.6.0 - 64bit Production

I have two Tables: ORDERS and ITEMS.

ORDERS looks like this

ORDERS

ITEMS looks like this

enter image description here

Table ORDERS has 1 or more Order_Number each assigned to at least one depot or more. the column Total_Value SHOULD store exactly the sum of the item values associated to an order number. the table ITEMS in fact stores via parcel_code items values for a specific order_number/s.

my db has a bug for orders that have more than one depot assigned to an order number (eg order number 1 and 4) do not store the actual total value correctly.

in my case I cannot figure out the UPDATE statement that would select order numbers that would take the sum from the table ITEMS and link it via parcel_code and update the column total_value in the table ORDERS.

the result of my update should give this back:

for table orders i should get back for

order number 1: for both rows total value 1120

order number 4 for both rows total value: 350

order number 2 and 3 as they are single depot order remain the same: 50 and 20

pseudo-code :

update ORDERS set total_value = (select sum(I.item_value) from ITEMS I, ORDERS O where O.parcel_code = I.parcel_code)

i would update also those orders which have on e depot assigned as they will exactly the same.

i was looking at MERGE statements or INNER select queries. the problem i am facing is that my update must be dynamic. this means not driven by values but by columns joins as i may have to create a process that update this every day.

can someone help me?

Answer 1

You need to join the items and orders tables together, then select the sum of all item_values where your order_number is equal to the row which you are updating (in table o1).

update 
Orders o1
set o1.total_value = (
    select sum(i.item_value) from Items i
    join Orders o2 on o2.parcel_code = i.parcel_code
    where o2.Order_number = o1.Order_number
)