What is the equivalent of the Oracle “Dual” table in MS SqlServer?

Question

What is the equivalent of the Oracle \"Dual\" table in MS SqlServer?

This is my Select:

SELECT pCliente,
       \'xxx.x.xxx.xx\' AS Serv         


        

Answer 1

While you usually don't need a DUAL table in SQL Server as explained by Jean-François Savard, I have needed to emulate DUAL for syntactic reasons in the past. Here are three options:

Create a DUAL table or view

-- A table
SELECT 'X' AS DUMMY INTO DUAL;

-- A view
CREATE VIEW DUAL AS SELECT 'X' AS DUMMY;

Once created, you can use it just as in Oracle.

Use a common table expression or a derived table

If you just need DUAL for the scope of a single query, this might do as well:

-- Common table expression
WITH DUAL(DUMMY) AS (SELECT 'X')
SELECT * FROM DUAL

-- Derived table
SELECT *
FROM (
  SELECT 'X'
) DUAL(DUMMY)