Home Next Previous 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 TypesNumeric Data TypesDate 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