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SQL Data Types

SQL data types 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 SQL Data Types:

Data 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

 

Approximate Numeric SQL Data Types:

Data Type

From

To

float

-1.79E + 308

1.79E + 308

real

-3.40E + 38

3.40E + 38

 

Date and Time Data Types:

Data Type

From

To

datetime

Jan 1, 1753

Dec 31, 9999

smalldatetime

Jan 1, 1900

Jun 6, 2079

date

Stores a date like June 30, 1991

 

time

Stores 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 SQL Data Types:

Data Type

From

To

char

char

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

varchar

varchar

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

varchar(max)

varchar(max)

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

text

text

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

 

Unicode Character Strings SQL Data Types:

Data Type

Description

nchar

Maximum length of 4,000 characters.( Fixed length Unicode)

nvarchar

Maximum length of 4,000 characters.(Variable length Unicode)

nvarchar(max)

Maximum length of 231characters (SQL Server 2005 only).( Variable length Unicode)

ntext

Maximum length of 1,073,741,823 characters. ( Variable length Unicode )

 

Binary SQL 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 SQL 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

 

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