Data Types

Exact Numeric Data Types

These data types store numeric values precisely. They are suitable for calculations where exact precision is critical, such as financial transactions.

Integer Types

Data Type	Storage Size	Range	Description
TINYINT	1 byte	0 to 255	Unsigned integer
SMALLINT	2 bytes	-32,768 to 32,767	Signed integer
INT	4 bytes	-2,147,483,648 to 2,147,483,647	Signed integer
BIGINT	8 bytes	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807	Signed integer

Approximate Numeric Data Types

Data Type	Storage Size	Precision	Range	Description
FLOAT	4 or 8 bytes	7 or 15 digits approx.	+/- 1.79E-308 to +/- 1.79E+308	Floating point number
REAL	4 bytes	7 digits approx.	+/- 1.79E-308 to +/- 1.79E+308	Floating point number (synonym for float(24))

Fixed Point Numeric Data Types

Data Type	Storage Size	Precision	Scale	Description
DECIMAL(p, s)	Variable	1 to 38	0 to p	Fixed precision and scale
NUMERIC(p, s)	Variable	1 to 38	0 to p	Synonym for DECIMAL
MONEY	8 bytes	19, 4	Four decimal places	Monetary values
SMALLMONEY	4 bytes	10, 4	Four decimal places	Smaller monetary values

Date and Time Data Types

These data types store date and time information. They are crucial for auditing, scheduling, and time-series analysis.

Data Type	Storage Size	Range	Precision	Description
DATE	3 bytes	January 1, 0001 to December 31, 9999	N/A	Date only
TIME	3-5 bytes	00:00:00.0000000 to 23:59:59.9999999	100 nanoseconds (configurable)	Time only
DATETIME	8 bytes	January 1, 1753 to December 31, 9999	3.33 milliseconds	Date and Time
DATETIME2(n)	6-8 bytes	January 1, 0001 to December 31, 9999	100 nanoseconds (configurable)	Date and Time with higher precision
SMALLDATETIME	4 bytes	January 1, 1900 to June 6, 2079	1 minute	Date and Time (less precise)
DATETIMEOFFSET(n)	8-10 bytes	January 1, 0001 to December 31, 9999	100 nanoseconds (configurable)	Date and Time with Time Zone Offset

Character String Data Types

These data types store textual data. They are essential for storing names, addresses, descriptions, and other text-based information.

Data Type	Storage	Max Length	Description
CHAR(n)	n bytes	8,000 characters	Fixed-length, non-Unicode string
VARCHAR(n)	2 bytes + data	8,000 characters	Variable-length, non-Unicode string
VARCHAR(MAX)	2 bytes + data	2 GB	Variable-length, non-Unicode string (large)
NCHAR(n)	2n bytes	4,000 characters	Fixed-length, Unicode string
NVARCHAR(n)	2n + 2 bytes	4,000 characters	Variable-length, Unicode string
NVARCHAR(MAX)	2n + 2 bytes	2 GB	Variable-length, Unicode string (large)
TEXT	Variable	2 GB	Non-Unicode string (deprecated)
NTEXT	Variable	2 GB	Unicode string (deprecated)

Binary String Data Types

These data types store binary data, such as images, files, or other raw byte sequences.

Data Type	Storage	Max Length	Description
BINARY(n)	n bytes	8,000 bytes	Fixed-length binary string
VARBINARY(n)	2 bytes + data	8,000 bytes	Variable-length binary string
VARBINARY(MAX)	2 bytes + data	2 GB	Variable-length binary string (large)
IMAGE	Variable	2 GB	Binary data (deprecated)

Other Data Types

This category includes a variety of specialized data types for different purposes.

Data Type	Storage	Description
BIT	1 bit	Stores 0, 1, or NULL. Used for Boolean values.
UNIQUEIDENTIFIER	16 bytes	Stores a GUID (Globally Unique Identifier).
XML	Variable	Stores XML data.
GEOGRAPHY	Variable	Stores geographic data (points, lines, polygons).
GEOMETRY	Variable	Stores spatial data (points, lines, polygons).
HIERARCHYID	Variable	Stores data in a hierarchy.
SQL_VARIANT	Variable	Stores values of various supported data types.
TABLE	Variable	Stores a result set for later use.