我如何确定“插入输出”的顺序正确？

Question

Let's say I have this @TempTable with only 2 columns ProductName and TempID :

ProductName | TempID  
------------+------
GTX 1080    | NULL
GTX 1080Ti  | NULL
RX 580      | NULL

I will insert this to TblProduct (2 columns: ProductName and ID ) with the following command:

INSERT INTO TblProduct (ProductName)
OUTPUT INSERTED.ID INTO @Test123(ID)
    SELECT ProductName 
    FROM @TempTable

Is it guaranteed that the output result in @Test123 is in correct order? Meaning that if the result is 1, 2, and 3.

• 1 should refer to GTX 1080
• 2 should refer to GTX 1080Ti
• 3 should refer to RX 580

Is it possible to update TempID in @TempTable from ID in @Test123 ? If yes, how? I was thinking of something like UPDATE ... SELECT ...

Answer 1

No, it's not guaranteed at all.
Tables in a relational database are unsorted by nature - in other words - the records have no inherent order.

However, you can output more than one column using the output clause, so for your sample data, you could output both ProductName and ID (of course, this means that the table variable @Test123 must have (at least) these two columns):

INSERT INTO TblProduct (ProductName)
OUTPUT INSERTED.ID, INSERTED.ProductName INTO @Test123(ID, ProductName)
SELECT ProductName 
FROM @TempTable

You can see a live demo on rextester

Answer 2

If you want the rows to appear in alphabetical order, as in your example then say:

select ProductName
from TblProduct
order by ProductName;

If you want some other order then you need a column that defines that order so that you can put the appropriate order on the select statement. For example, if you want to get the rows back in the order you inserted them, define your table as:

create table TblProduct
(
    id             int identity(1,1) not null,
    ProductName    varchar(20),
    tempID         int
);

then

select ProductName
from TblProduct
order by id;