# 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) | <p>Fixed precision and scale numbers.</p><p>Allows numbers from -10^38 +1 to 10^38 –1.</p> | 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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