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Sql data types example

In any programming language, there are some standard defined data types, even in SQL (Structured Query Language) which is used for database programming, has some certain data type, here you learn all sql data types with example.

Data Types in SQL is an attribute, which tells the type of data of any column, variable and expression has a related data type in Sql.

sql data types

As you can see in above picture diagram, you can define data type while creating a table, also can alter the data type for any particular column, however if there is data of different type which are not convertible, that that may cause an error.

Different data types in Sql

Here is the SQL code of defining sql data type at the time of creating or altering a Table

Create TABLE [dbo].[tbWeek](
	[WeekId] [int] IDENTITY(1,1) NOT NULL,
	[WeekName] [varchar](50) NOT NULL,
	[UpdateDate] [datetime] NOT NULL,
	[CreateDate] [date] NULL,
	[NoOfHolidays] [int] NULL,
	[WeekId] ASC
Alter Column Data Type in SQL Table

Here is an example of how you can alter column data type in sql table.

Notice, when i created the table with above script, the column "WeekName" was defined as Varchar data type, now i change the data type to nvarchar data type.

ALTER COLUMN [WeekName] nvarchar(50);

Here are the different data type examples in SQL Database

String data types in sql database

All different type string data type that sql server supports.

  • char
    Max length of 8,000 characters (non-Unicode characters, fixed length)
  • varchar
    Max of 8,000 characters.(non-Unicode data, variable-length )
  • text
    Max length of 2,147,483,647 characters (variable length, non-Unicode data)
  • nchar
    Max length of 4,000 characters (unicode characters, fixed length)
  • nvarchar
    Max length of 4,000 characters (unicode characters, variable length)
  • ntext
    Max length of 1,073,741,823 characters. ( unicode, variable length)
Numeric data types in sql database

Here are different type numeric data type that sql server supports.

  • bigint: -+9,223,372,036,854,775,807
  • int: -+2,147,483,648
  • numeric: 10^38 -1
  • decimal: 100000.000001
  • bit: 0 or 1 (boolean)
  • money: +- 922,337,203,685,477.5808
  • smallmoney: +- 214,748.3648
Sql date data types
datetime, smalldatetime, date, time

Learn more about sql datetime functions and data type

Sql binary data types
  • binary
    Max length of 8,000 bytes(binary data, fixed length )
  • varbinary
    Max length of 8,000 bytes.(binary data, variable length)
  • image
    Max length of 2,147,483,647 bytes (binary data, variable length)
Misc data types in sql database
  • uniqueidentifier
    Stores a GUID ( globally unique identifier )
  • xml
    Stores XML data.
  • timestamp
    unique number that gets updated every time a row gets updated
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