There are 4 ways to convert a numeric expression from one data type to another data type:

* Implicit conversion by arithmetic operations - When arithmetic operations are performed on expressions of different data types, implicit data type conversion will be performed before the arithmetic operation on the expression with a lower data type rank.

* Implicit conversion by assignment operations - When a numeric expression is assigned to variable, column, or parameter of different data type, the expression will be converted to match the data type of the variable, column, or parameter.

* Explicit conversion using the CAST() function - A numeric expression can be explicitly converted to different data type using the CAST(expression AS data_type) function.

* Explicit conversion using the CONVERT() function - A numeric expression can be explicitly converted to different data type using the CONVERT(data_type, expression) function.

Some numeric data type conversion examples are provided in the tutorial exercise below:

-- Implicit conversion by an arithmetic operation

-- INT converted to NUMERIC

DECLARE @d NUMERIC(9,6);

SET @d = 1.0;

SELECT @d/3;

GO

0.33333333

-- Implicit conversion by an assignment operation

-- NUMERIC converted to INT

DECLARE @i INT;

DECLARE @d NUMERIC(9,3);

SET @d = 123.456;

SET @i = @d;

SE