Data Types

SQL Data Type is a specified attribute for any object's data type. There is an associated data type in SQL in each column, variable and expression. When designing your tables, you can use various types of data, and you can select a data type based on your requirements for a table column.

SQL Server provides six data types categories, described below –

Exact Numeric Data Types

DATA TYPE
bigint
int
smallint
tinyint
bit
decimal
numeric
money
smallmoney

Approximate Numeric Data Types

DATA TYPE
float
real

Date and Time Data Types

DATA TYPE
datetime
smalldatetime
date
time

Character Strings Data Types

Sr.No DATA TYPE & Description
1 char
8,000 characters of maximum length. (Non-Unicode characters with fixed length)
2 varchar
Maximum 8,000 characters of varchar. (Non-Unicode data variable-length)
3 varchar(max)
2E + 31 characters maximum, non-Unicode data variable-length (SQL Server 2005 only).
4 text
Non-Unicode variable length data of 2 147,483,647 characters for a maximum length.

Unicode Character Strings Data Types

Sr.No DATA TYPE & Description
1 nchar
Max length = 4,000 characters
2 nvarchar
Max length = 4,000 characters
3 nvarchar(max)
Max length = 2E + 31 characters
4 ntext
Max length = 1,073,741,823 characters

Binary Data Types

Sr.No DATA TYPE & Description
1 Binary 
Up to 8,000 bytes Length (Fixed-length binary data )
2 varbinary
8,000 bytes of maximum length. (Binary data for variable length)
3 varbinary(max)
2E Plus 31 bytes maximum length (SQL Server 2005 only). (Binary data for variable length)
4 image
Most 2.147.483.647 bytes of length. (Binary Data variable length)

Misc Data Types

Sr.No DATA TYPE & Description
1 sql variant
Stores values of several types of data provided by SQL Server, with the exception of text, ntext and time signs.
2 Timestamp 
Specifies a unique database number that is updated each time a row is updated.
3 Unique identification 
Store a global unique xml GUID Store XML Data.  
4 xml
xml instances can be stored in a column or a variable (SQL Server 2005 only).
5 cursor
Reference to a cursor object
6 table
Stores a result set for later processing