precedence order for data types in SQL Server 2008

user-defined data types (highest)

sql_varian t

xml

datetimeoffset

datetime2

datetime

smalldatetime

date

time

float

real

decimal

money

smallmoney

bigint

int

smallint

tinyint

bit

ntext

text

image

timestamp

uniqueidentifier

nvarchar (including nvarchar(max) )

nchar

varchar (including varchar(max) )

char

varbinary (including varbinary(max) )

binary (lowest)