Function return table variable - sql

Question

I'm trying to create a function that return a table variable.So firstly i get data from Table1 and put it in another table variable. Here i want check if this variable isempty the function return the parameter result else return the result of the table variable
The function script is bellow :
USE[DATABase1]
GO
IF OBJECT_ID (N'CodeFunc', N'TF') IS NOT NULL DROP FUNCTION dbo.CodeFunc;
GO
CREATE FUNCTION CodeFunc ( #Code nvarchar(4) , #Table nvarchar(40) = '' )
RETURNS #VirtualDAT TABLE
(
RowID INT IDENTITY ( 1 , 1 ),
Code nvarchar(400)
)
AS
BEGIN
DECLARE #CodeM nvarchar(400)
DECLARE #imax INT SET #imax = ##ROWCOUNT
DECLARE #i INT SET #i = 1
DECLARE #SelectDAT TABLE
(
RowID INT IDENTITY ( 1 , 1 ),
Code nvarchar(400)
)
INSERT #SelectDAT
SELECT Code FROM table1
WHERE table1.id = 41
IF(EXISTS (SELECT 1 FROM #SelectDAT))
BEGIN
WHILE (#i <= #imax)
BEGIN
SELECT #CodeM = Code FROM #SelectDAT WHERE RowID = #i
INSERT INTO #VirtualDAT(Code) VALUES (#CodeM)
SET #i = #i + 1
END
END
ELSE
INSERT INTO #VirtualDAT(Code) VALUES (#Code)
RETURN
END
So this script works without put it inside function.
And i test this function like this :SELECT * FROM dbo.CodeFunc( 'toto',Default ) the result is :
IF(EXISTS (SELECT 1 FROM #SelectDAT)) no record returned
esle the result is ok

Answer 1

As VR46 says. The ##ROWCOUNT will be set to 0 because there is no query before it. Any code executing in a function happens as a seperate set of queries. It was probably returning a value outside the function because you had previously used the query window for another unrelated query
You could re-factor this function quite dramatically. Look below, ##ROWCOUNT will work here as it is just after the insert query and will definitely have a value based on the insert.
I have not been able to test this, but I think something like this should do the same job.
USE[DATABase1]
GO
IF OBJECT_ID (N'CodeFunc', N'TF') IS NOT NULL DROP FUNCTION dbo.CodeFunc;
GO
CREATE FUNCTION CodeFunc ( #Code nvarchar(4) , #Table nvarchar(40) = '' )
RETURNS #VirtualDAT TABLE
(
RowID INT IDENTITY ( 1 , 1 ),
Code nvarchar(400)
)
AS
BEGIN
insert into #VirtualDAT
Select Code from table1 where table1.id = 41
if ##ROWCOUNT = 0
begin
INSERT INTO #VirtualDAT(Code) VALUES (#Code)
end
RETURN
END

Answer 2

Since you are assigning #imax with ##ROWCOUNT right after declaration of variable will be initialized with zero.
From MSDN ##ROWCOUNT
Returns the number of rows affected by the last statement.
If am not wrong you need to assign value to #imax after the insert into..select query.
INSERT #SelectDAT
SELECT Code FROM table1
WHERE table1.id = 41
SET #imax= ##ROWCOUNT
You can do the same in SET BASED APPROACH without using while loop.
CREATE FUNCTION Codefunc (#Code NVARCHAR(4),
#Table NVARCHAR(40) = '')
returns #VirtualDAT TABLE (
rowid INT IDENTITY ( 1, 1 ),
code NVARCHAR(400))
AS
BEGIN
IF EXISTS (SELECT code
FROM table1
WHERE table1.id = 41)
BEGIN
INSERT INTO #VirtualDAT
(code)
SELECT code
FROM table1
WHERE table1.id = 41
END
ELSE
INSERT INTO #VirtualDAT
(code)
VALUES (#Code)
RETURN
END