SQL Data Types

SQL data type is an attribute that specifies type of data of any object. Each column, variable and expression has related data type in SQL.

You would use these data types while creating your tables. You would choose a particular data type for a table column based on your requirement.

SQL Server offers six categories of data types for your use:

Exact Numeric Data Types:

DATA TYPEFROM

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

 

Approximate Numeric Data Types:

DATA TYPEFROM

TO

Float-1.79E + 308

1.79E + 308

Real-3.40E + 38

3.40E + 38

 

Date and Time Data Types:

DATA TYPEFROMTO
DatetimeJan 1, 1753Dec 31, 9999
smalldatetimeJan 1, 1900Jun 6, 2079
DateStores a date like June 30, 1991
TimeStores a time of day like 12:30 P.M.

Note: Here datetime has 3.33 milliseconds accuracy where as smalldatetime has 1 minute accuracy.

Character Strings Data Types:

DATA TYPEFROM

TO

Char                              Char                                Maximum length of 8,000 characters. (Fixed length non-Unicode characters)
VarcharVarchar

Maximum of 8,000 characters.(Variable-length non-Unicode data).

 

varchar(max)varchar(max)

Maximum length of 231 characters,Variable-length non-Unicode data(SQL Server 2005 only)

Texttext

Variable-length non-Unicode data with a maximum length of 2,147,483,647 characters.

 

Unicode Character Strings Data Types:

DATA TYPE

Description

NcharMaximum length of 4,000 characters.( Fixed length Unicode)
NvarcharMaximum length of 4,000 characters.(Variable length Unicode)
nvarchar(max)Maximum length of 231 characters (SQL Server 2005 only).(Variable length Unicode)
NtextMaximum length of 1,073,741,823 characters. ( Variable length Unicode )

 

Binary Data Types:

DATA TYPE Description
Binary Maximum length of 8,000 bytes(Fixed-length binary data )
Varbinary Maximum length of 8,000 bytes.(Variable length binary data)
varbinary(max) Maximum length of 231 bytes (SQL Server 2005 only). ( Variable length Binary data)
Image Maximum length of 2,147,483,647 bytes. ( Variable length Binary Data)

 

Misc Data Types:

 DATA TYPE

Description

 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

Reference to a cursor object

 table     Stores a result set for later processing