Question

I have a UDF which returns table variable like

--
--
RETURNS @ElementTable TABLE
(
    ElementID INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
    ElementValue VARCHAR(MAX)
)
AS
--
--

Is the order of data in this table variable guaranteed to be same as the order data is inserted into it. e.g. if I issue

INSERT INTO @ElementTable(ElementValue) VALUES ('1')
INSERT INTO @ElementTable(ElementValue) VALUES ('2')
INSERT INTO @ElementTable(ElementValue) VALUES ('3')

I expect data will always be returned in that order when I say

select ElementValue from @ElementTable  --Here I don't use order by 

EDIT:

If order by is not guaranteed then the following query

SELECT T1.ElementValue,T2.ElementValue FROM dbo.MyFunc() T1
Cross Apply dbo.MyFunc T2
order by t1.elementid

will not produce 9×9 matrix as

1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3

consistently.

Is there any possibility that it could be like

1 2
1 1
1 3
2 3
2 2
2 1
3 1
3 2
3 3

How to do it using my above function?

Answer 1

Given your update, you obtain it in the obvious way – you ask the system to give you the results in the order you want:

SELECT T1.ElementValue,T2.ElementValue FROM dbo.MyFunc() T1
Cross join dbo.MyFunc() T2
order by t1.elementid, t2.elementid

You are guaranteed that if you’re using inefficient single row inserts within your UDF, that the IDENTITY values will match the order in which the individual INSERT statements were specified.