SQL SERVER Topic

Data Types in SQL SERVER
SQL developers have to decide what types of data will be stored inside each and every table column when creating a SQL table. The data type is a label and a guideline for SQL to understand what type of data is expected inside of each column, and it also identifies how SQL will interact with the stored data.

There are six types of Data Types in SQL SERVER:-
  1. Exact Numeric Data Types
  2. Character Strings Data Types
  3. Date and Time Data Types
  4. Binary Data Types
  5. Unicode Character Strings Data Types
  6. Approximate Numeric Data Types
  7. Misc Data Types


1. 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


2. Character Strings 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.



3. 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.



4. 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)



5. Unicode Character Strings 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 )


6. Approximate Numeric Data Types :-

DATA TYPE FROM TO
float -1.79E + 308 1.79E + 308
real -3.40E + 38 3.40E + 38


7. 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