select CAST(CAST('2002-09-30' AS datetime) - CAST('2001-12-01' AS datetime) AS int)

 


2>
3> select CAST(CAST('2002-09-30' AS datetime) - CAST('2001-12-01' AS datetime) AS int)
4> GO

-----------
        303

(1 rows affected)
1>

1.	CAST(expression AS data type(<length>))
2.	CAST (original_expression AS desired_datatype)
3.	CAST(2.78128 AS integer)
4.	CAST(2.78128 AS money)
5.	CAST('11/11/72' as smalldatetime) AS '11/11/72'
6.	select CAST('2002-09-30 11:35:00' AS smalldatetime) + 1 (plus)
7.	select CAST('2002-09-30 11:35:00' AS smalldatetime) - 1 (minus)
8.	The CAST() function accepts one argument, an expression
9.	Mixing Datatypes: CAST and CONVERT
10.	Cast date type to char
11.	CAST can still do date conversion
12.	Cast date to different format
13.	Cast number to varchar and use the regular expressions
14.	Conversion with CONVERT function for computated value with numbers in list
15.	Cast int to decimal
16.	Convert varchar to number
17.	CONVERT() does the same thing as the CAST() function
18.	CAST(ID AS VarChar(5))
19.	CAST('123.4' AS Decimal)
20.	Arithmetic overflow error converting numeric to data type varchar.

select CAST(CAST('2002-09-30' AS datetime) - CAST('2001-12-01' AS datetime) AS int) : Cast « Data Type « SQL Server / T-SQL