SQL Server 2008 - How do i return a User-Defined Table Type from a Table-Valued Function?
Sql ServerTsqlSql Server-2008User Defined-FunctionsUser Defined-TypesSql Server Problem Overview
Here's my user-defined table type...
CREATE TYPE [dbo].[FooType] AS TABLE(
[Bar] [INT],
)
This is what ive had to do in my table-valued function to return the type:
CREATE FUNCTION [dbo].[GetFoos]
RETURN @FooTypes TABLE ([Bar] [INT])
INSERT INTO @FooTypes (1)
RETURN
Basically, im having to re-declare my type definition in the RETURN statement of the function. Isnt there a way i can simply declare the type in the RETURN statement?
I would have thought this would work:
CREATE FUNCTION [dbo].[GetFoos]
RETURN @FooTypes [FooType]
INSERT INTO @FooTypes (1)
RETURN
Cannot find any help on MSDN/Google regarding this....anyone?
EDIT
I unmarked my answer, and bumping this question - as i am encountering the same scenario 6 months later.
Does anyone have any idea if it's possible to return a user defined table type from a table valued function? If not, is there a better workaround other than what i have done? (re-declare the type again).
Sql Server Solutions
Solution 1 - Sql Server
Even though you can not return the UDTT from a function, you can return a table variable and receive it in a UDTT as long as the schema match. The following code is tested in SQL Server 2008 R2
-- Create the UDTT
CREATE TYPE dbo.MyCustomUDDT AS TABLE
(
FieldOne varchar (512),
FieldTwo varchar(1024)
)
-- Declare your variables
DECLARE @uddt MyCustomUDDT;
DECLARE @Modifieduddt MyCustomUDDT;
// Call the function
INSERT INTO @Modifieduddt SELECT * FROM dbo.MyUDF(@uddt);
Function signature
CREATE FUNCTION dbo.MyUDF(@localUDDT MyCustomUDDT)
RETURNS @tableVar TABLE
(
FieldOne varchar (512),
FieldTwo varchar(1024)
)
AS
BEGIN
--Modify your variable here
RETURN
END
Hopefully this will help somebody.
Solution 2 - Sql Server
Ok - so it cant be done.
Easy enough to duplicate the table definition in the return type (with the use of scripting).
Still - hopefully this issue gets rectified in the next version of SQL Server.
Solution 3 - Sql Server
The syntax for CREATE FUNCTION indicates that the only way to define a table return type is by listing columns and types, a <table_type_definition>
. Even SQL Server "Denali" has the same definition for <table_type_definition>
. Although strangely, it's syntax doesn't include multi-statement Table valued functions, or anything else that references this fragment.
Solution 4 - Sql Server
I do not believe this is possible. You cannot use a UDTT as the return type of a Scalar-Valued Function because it is not a scalar value. You also cannot replace the table declaration of a Table-Valued Function with a UDTT. Repeating the table definition seems to be the only option. If we knew why you were doing this, perhaps we could find an alternative.