Data Types

                  Before knowing various data types, you must know what is actually a data type. A data type is an attribute which indicates what kind of data (characters, numbers, dates etc) will be held in a column. Following is the list of data types in Sql server.

Exact numerics

Type	From	To
bigint	-9,223,372,036,854,775,808	9,223,372,036,854,775,807
int	-2,147,483,648	2,147,483,647
smallint	-32,768	32,767
tinyint	0	255
bit	0	1
decimal	-10^38 +1	10^38 –1
numeric	-10^38 +1	10^38 –1
money	-922,337,203,685,477.5808	+922,337,203,685,477.5807
smallmoney	-214,748.3648	+214,748.3647

numeric and decimal are Fixed precision and scale data types and are functionally equivalent.

Approximate numerics

Type	From	To
float	-1.79E + 308	1.79E + 308
real	-3.40E + 38	3.40E + 38

datetime and smalldatetime

Type	From	To
datetime (3.33 milliseconds accuracy)	Jan 1, 1753	Dec 31, 9999
smalldatetime (1 minute accuracy)	Jan 1, 1900	Jun 6, 2079

Character Strings

Type	Description
char	Fixed-length non-Unicode character data with a maximum length of 8,000 characters.
varchar	Variable-length non-Unicode data with a maximum of 8,000 characters.
varchar(max)	Variable-length non-Unicode data with a maximum length of 231 characters (SQL Server 2005 only).
text	Variable-length non-Unicode data with a maximum length of 2,147,483,647 characters.

Unicode Character Strings

Type	Description
nchar	Fixed-length Unicode data with a maximum length of 4,000 characters.
nvarchar	Variable-length Unicode data with a maximum length of 4,000 characters.
nvarchar(max)	Variable-length Unicode data with a maximum length of 230 characters (SQL Server 2005 only).
ntext	Variable-length Unicode data with a maximum length of 1,073,741,823 characters.

Binary Strings

Type	Description
binary	Fixed-length binary data with a maximum length of 8,000 bytes.
varbinary	Variable-length binary data with a maximum length of 8,000 bytes.
varbinary(max)	Variable-length binary data with a maximum length of 231 bytes (SQL Server 2005 only).
image	Variable-length binary data with a maximum length of 2,147,483,647 bytes.

Other Data Types

• sql_variant: Stores values of various SQL Server-supported data types, except text, ntext, and timestamp.
• timestamp: Stores a database-wide unique number that gets updated every time a row gets updated.
• uniqueidentifier: Stores a globally unique identifier (GUID).
• xml: Stores XML data. You can store xml instances in a column or a variable (SQL Server 2005 only).
• cursor: A reference to a cursor.
• table: Stores a result set for later processing.