SQL data types
String data types
Data type | Description | Max 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 | 1,073,741,824 characters | 2 bytes + number of chars |
text | Variable width character string | 2GB of text data | 4 bytes + number of chars |
nchar | Fixed width Unicode string | 4,000 characters | Defined width x 2 |
nvarchar | Variable width Unicode string | 4,000 characters | |
nvarchar(max) | Variable width Unicode string | 536,870,912 characters | |
ntext | Variable width Unicode string | 2GB of text data | |
binary(n) | Fixed width binary string | 8,000 bytes | |
varbinary | Variable width binary string | 8,000 bytes | |
varbinary(max) | Variable width binary string | 2GB | |
image | Variable width binary string | 2GB |
Numeric data types
Data type | Description | Storage |
bit | Integer that can be 0, 1, or NULL | |
tinyint | Allows whole numbers from 0 to 255 | 1 byte |
smallint | Allows whole numbers between -32,768 and 32,767 | 2 bytes |
int | Allows whole numbers between -2,147,483,648 and 2,147,483,647 | 4 bytes |
bigint | Allows whole numbers between -9,223,372,036,854,775,808 and 9,223,372,036,854,775,807 | 8 bytes |
decimal(p,s) | Fixed precision and scale numbers. Allows numbers from -10^38 +1 to 10^38 –1. | 5-17 bytes |
numeric(p,s) | Decimal and numeric are synonyms and can be used interchangeably. | 5-17 bytes |
smallmoney | Monetary data from -214,748.3648 to 214,748.3647 | 4 bytes |
money | Monetary data from -922,337,203,685,477.5808 to 922,337,203,685,477.5807 | 8 bytes |
float(n) | Floating precision number data from -1.79E+308 to 1.79E+308. | 4 or 8 bytes |
real | Floating precision number data from -3.40E+38 to 3.40E+38 | 4 bytes |
Date and Time data types
Data type | Description | Storage |
datetime | From January 1, 1753 to December 31, 9999 with an accuracy of 3.33 milliseconds | 8 bytes |
datetime2 | From January 1, 0001 to December 31, 9999 with an accuracy of 100 nanoseconds | 6-8 bytes |
smalldatetime | From January 1, 1900 to June 6, 2079 with an accuracy of 1 minute | 4 bytes |
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 |
datetimeoffset | The same as datetime2 with the addition of a time zone offset | 8-10 bytes |
timestamp | Stores a unique number that gets updated every time a row gets created or modified. The timestamp value is based upon an internal clock and does not correspond to real time. |
Other data types
Data type | Description |
sql_variant | Stores up to 8,000 bytes of data of various data types, except text, ntext, and timestamp |
uniqueidentifier | Stores a globally unique identifier (GUID) |
xml | Stores XML formatted data. Maximum 2GB |
cursor | Stores a reference to a cursor used for database operations |
table | Stores a result-set for later processing |
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