We walk in the dark places no others will enter
We stand on the bridge and no one may pass

-- scalar function
DROP FUNCTION GetAmount;
GO
CREATE FUNCTION GetAmount(@productId INT)
   RETURNS DECIMAL(15,5)
AS
BEGIN
   RETURN 1.234;
END
GO

DECLARE @amount DECIMAL(15,5);
SELECT @amount = dbo.GetAmount(123);
PRINT @amount;
GO

-- get SELECT into a variable
DECLARE @table_name NVARCHAR(128);

SELECT TOP(1)
      @table_name = TABLE_NAME
   FROM INFORMATION_SCHEMA.TABLES;

PRINT @table_name;

USE tempdb;
GO
-- Three related tables
CREATE TABLE dbo.T1 (PK INT IDENTITY PRIMARY KEY, A INT NULL);
CREATE TABLE dbo.T2 (PK INT IDENTITY PRIMARY KEY, B INT NULL);
CREATE TABLE dbo.T3 (PK INT IDENTITY PRIMARY KEY, C INT NULL);
GO
-- Sample data
INSERT dbo.T1 (A) VALUES (1), (2), (3);
INSERT dbo.T2 (B) VALUES (-4), (-5), (-6);
INSERT dbo.T3 (C) VALUES (14), (28), (36);
GO
-- View to create a sort of 'cross-table' computed column
-- Index the view if appropriate, to materialize the 'computed column'
CREATE VIEW dbo.V 
WITH SCHEMABINDING
AS
SELECT  T1.PK,
        Value = T1.A * PI() + T2.B + LOG10(T3.C)
FROM    dbo.T1
JOIN    dbo.T2 ON T2.PK = T1.PK
JOIN    dbo.T3 ON T3.PK = T2.PK;
GO
-- Show the contents of the view
SELECT  PK, Value
FROM    dbo.V;
GO
-- Tidy up
DROP VIEW dbo.V;
DROP TABLE dbo.T1, dbo.T2, dbo.T3;