SQL - Data Types


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SQL Data Type is an attribute that specifies the type of data of any object. Each column, variable and expression has a related data type in SQL. You can use these data types while creating your tables. You can choose a data type for a table column based on your requirement.

SQL Server offers six categories of data types for your use which are listed below −

Exact Numeric 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 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 Data Types

Sr.No. DATA TYPE & Description
1

char

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

2

varchar

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

3

varchar(max)

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

4

text

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

Unicode Character Strings Data Types

Sr.No. DATA TYPE & Description
1

nchar

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

2

nvarchar

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

3

nvarchar(max)

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

4

ntext

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

Binary Data Types

Sr.No. DATA TYPE & Description
1

binary

Maximum length of 8,000 bytes(Fixed-length binary data )

2

varbinary

Maximum length of 8,000 bytes.(Variable length binary data)

3

varbinary(max)

Maximum length of 231 bytes (SQL Server 2005 only). ( Variable length Binary data)

4

image

Maximum length of 2,147,483,647 bytes. ( Variable length Binary Data)

Misc Data Types

Sr.No. DATA TYPE & Description
1

sql_variant

Stores values of various SQL Server-supported data types, except text, ntext, and timestamp.

2

timestamp

Stores a database-wide unique number that gets updated every time a row gets updated

3

uniqueidentifier

Stores a globally unique identifier (GUID)

4

xml

Stores XML data. You can store xml instances 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



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