SQL DATA TYPES
DATA TYPES are used to store the type of data that can be stored in a column of a database table.
  There are three categories of data types.
String Data Types
Numeric Data Types
Date and Time Data Types
String Data Types
Data Types
Description
Size
Storage
char(n)
Fixed width character string
8,000 characters
Defined width
varchar(n)
variable width character string
8,000 characters
2 bytes + number of chars
varchar(max)
variable width character string
1073741824 characters
2 bytes + number of chars
nchar(n)
variable width unicode string
4000 characters
nvarchar(n)
variable width unicode string
536870912 characters
nvarchar(max)
variable width unicode string
536870912 characters
Numeric Data Types
Data Types
Description
Storage
bit
0,1 or null
tinyint
whole numbers from 0 to 255
1 byte
smallint
whole numbers from -32,768 to 32,767
2 byte
int
whole numbers from -2,147,483,648 and 2,147,483,647
4 byte
bigint
whole numbers from -9,223,372,036,854,775,808 and 9,223,372,036,854,775,807
8 byte
Date Data Types
Data Type
Description
Storage
Date
Store a date only. From January 1, 0001 to December 31, 9999
3 bytes
Time
Store a time only to an accuracy of 100 nanoseconds
3-5 bytes
datetime
From January 1, 1753 to December 31, 9999 with an accuracy of 3.33 milliseconds
8 bytes
smalldatetime
From January 1, 1900 to June 6, 2079 with an accuracy of 1 minute
4 bytes