SQL Views - no variables?

Is it possible to declare a variable within a View? For example:

Declare @SomeVar varchar(8) = 'something'

gives me the syntax error:

Incorrect syntax near the keyword 'Declare'.


You are correct. Local variables are not allowed in a VIEW.

You can set a local variable in a table valued function, which returns a result set (like a view does.)

http://msdn.microsoft.com/en-us/library/ms191165.aspx

e.g.

CREATE FUNCTION dbo.udf_foo()
RETURNS @ret TABLE (col INT)
AS
BEGIN
  DECLARE @myvar INT;
  SELECT @myvar = 1;
  INSERT INTO @ret SELECT @myvar;
  RETURN;
END;
GO
SELECT * FROM dbo.udf_foo();
GO

You could use WITH to define your expressions. Then do a simple Sub-SELECT to access those definitions.

CREATE VIEW MyView
AS
  WITH MyVars (SomeVar, Var2)
  AS (
    SELECT
      'something' AS 'SomeVar',
      123 AS 'Var2'
  )

  SELECT *
  FROM MyTable
  WHERE x = (SELECT SomeVar FROM MyVars)

EDIT: I tried using a CTE on my previous answer which was incorrect, as pointed out by @bummi. This option should work instead:

Here's one option using a CROSS APPLY, to kind of work around this problem:

SELECT st.Value, Constants.CONSTANT_ONE, Constants.CONSTANT_TWO
FROM SomeTable st
CROSS APPLY (
    SELECT 'Value1' AS CONSTANT_ONE,
           'Value2' AS CONSTANT_TWO
) Constants