CREATE FUNCTION failed because a column name is not specified for column %d.

Error Message:
Msg 4514, Level 16, State 1, Procedure myfunction, Line 6
CREATE FUNCTION failed because a column name is not specified for column %d.

Severity level:
16.

Description:
This error message appears when you try to create a user-defined function in which for at least one column no explicite name was specified or SQL Server wasn't able to deduct such a column name.

Consequences:
The T-SQL statement can be parsed, but causes the error at runtime.

Resolution:
Errors of the Severity Level 15 are generated by the user and are corrigible by the user. The statement cannot be executed this way. Each column in a table-valued user-defined function must have a unique name.

Versions:
All versions of SQL Server.

Example(s):
USE Northwind
IF OBJECT_ID ('dbo.myfunction') > 0
 DROP FUNCTION dbo.myfunction;
GO
CREATE FUNCTION dbo.myfunction (@CustomerID nchar(5))
RETURNS TABLE
AS
RETURN
(
 SELECT *, 1
   FROM Northwind.dbo.Orders
  WHERE CustomerID = @CustomerID
);
GO
SELECT * FROM dbo.myfunction ('ALFKI');

Remarks:
A single SELECT statement such as

 SELECT CustomerID, COUNT(*)
   FROM Northwind.dbo.Orders
  WHERE CustomerID = @CustomerID
  GROUP BY CustomerID

works fine even with the missing column name for the COUNT(*) expression. In this case will SQL Server automatically assign a dummy name. However, this does not work for table-valued functions.