SQL Data Types

The SQL data type is an attribute that specifies the type of data an object can hold. For instance, character data (string data), binary data, integer data, financial data, date and time data, and so on. The following data types are special SQL data types to store geographical data.

  • Geometry Data type: This data type is used to represent the data in a two-dimensional Euclidean coordinate system
  • Geography Datatype: The functionality of this Sql Server datatype is the same as the Geometry. The only difference between both these data types is, when you declare the variable with Geography data type, you are specifying the points in terms of latitude and longitude.

List of available SQL Data Types

The following are the available list of SQL server Data Types and their description.

SQL Numeric Data Type

The following are the available list of numerical data types in SQL Server

SQL Data TypesDescriptionLength
intStores the integer values ranging from -2,147,483,648 to 2,147,483,6474 Bytes
tinyintStores the integer values ranging from 0 to 2551 Byte
smallintAccept integer values ranging from -32,768 to 32,7672 Byte
bigintIt stores the integer values ranging from -253 to -253 – 18 Bytes
moneyIt stores the financial values ranging from -922,337,203,685,477.5808 to -922,337,203,685,477.58078 Bytes
smallmoneyIt stores the financial values ranging from -214,748.3648 to 214,748.36474 Bytes
decimal(p,s)It stores the decimal values. Here p is the Precision, s is the Scale, and the maximum precision value is 38 digits.5 – 17 Bytes
numeric(p,s)Functionality of this data type is equivalent to decimal (p, s).5 – 17 Bytes
float(n)It stores the floating point values with precision of 7 digit (if n = 24, and 15 digit (if n = 53).5 – 17 Bytes5 – 17 Bytes If n = 24 it uses 4 Bytes, and If n = 53 it uses 8 Bytes
realFunctionality of this data type is equivalent to float(24).4 Bytes

SQL Character and String Data Types

These SQL data types stores n Unicode characters 2n Bytes, where the range of n is from 1 to 4000.

SQL DataTypesDescription & Length
char(n)It stores n characters Bytes, where the range of n is from 1 to 8000.
nchar(n)It stores approximately n characters Actual string length + 2 Byte, where the range of n is from 1 to 8000
varchar(n)It stores up to 231-1 characters. Length = Actual string length + 2 Byte
varchar(max)It stores approximately n characters2n(Actual string length) + 2 Byte, where the range of n is from 1 to 8000
nvarchar(n)It stores up to ((231-1) /2) – 2 characters
nvarchar(max)It stores up to ((2n-1) /2) – 2 characters. 2n(Actual string length) + 2 Byte

SQL Binary Data Types

SQL DataTypesDescriptionLength
bitIt stores a single bit of data1 byte for 8-bit column
binary(n)It stores n bytes of binary datan Bytes, where the range of n is from 1 to 8000
varbinary(n)It stores approximately n bytes of binary dataActual string length + 2 Byte, where the range of n is from 1 to 8000
varbinary(max)It stores up to 231-1 bytes of binary dataActual string length + 2 Byte

SQL Date and Time Data Types

Data TypesDescriptionLengthExample
dateIt stores dates between January 01, 0001, and December 31, 99993 Bytes2016-08-19
DateTimeIt stores date and time between January 01, 1753, and December 31, 99998 Bytes2016-08-19 10:15:45.0110
datetime2It stores date and time between January 01, 0001, and December 31, 99996 – 8 Bytes2016-08-19 10:15:45.0110112
datetimeoffsetIt is same as datetime2, and in addition, it will include the Universal Time Coordinate (UTC) offset (we also called as GMT)8 – 10 Bytes2016-08-19 10:15:45.0110112 +05:30
smalldatetimeIt stores date and time between January 01, 1990, and June 06, 20794 Bytes2016-08-19
timeIt stores time with an accuracy of 100 nanoSeconds. The time range is between 00:00:00.0000000, and 23:59:59.99999993 – 5 Bytes10:15:45.0110136

Difference between Char and Varchar, Nvarchar data types in SQL Server

Char Data Type in SQL Server

Character or Char data type in Sql Server is used to store the fixed length of characters.

For example, if we declare variable, @str CHAR (50) means the SQL server will allocate memory for 50 characters. Suppose we inserted 10 characters into a @str variable, 10 characters of memory used, and the remaining 40 characters will waste.

Varchar Data Type in SQL Server

A Varchar data type in Sql Server means variable character, and it is used to store the non-Unicode characters. Varchar allocates the memory based on the number of characters inserted into it.

For example, if we declare variable, @name VARCHAR (50) means, it will allocate memory for 0 characters. Suppose we inserted 10 characters into a @name variable. Then, this SQL data type will allocate the memory to store those 10 characters (it allocate literally 10 characters and no wastage). If you think that the size of the column data might exceed 8000 bytes, please use Varchar(max).

NVarchar DataType in SQL Server

NVarchar data type in Sql Server is the same as the Varchar data type. The only difference between them is, it is used to store Unicode characters. NVarchar data type will take double (2n) space to store the other language characters. If you think that the size of the column data might exceed 4000 bytes, please use nvarchar(max).

NOTE: When you are not storing other language characters then, I suggest you choose Varchar