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SQL - data types
Data Types
SQL Data Type is an attribute that specifies the type of data of any object. Each column, variable and expression has a related data type in SQL. You can use these data types while creating your tables. You can choose a data type for a table column based on your requirement.
SQL Server offers six categories of data types for your use which are listed below −
Exact Numeric Data Types
| DATA TYPE | FROM | TO |
|---|---|---|
| bigint | -9,223,372,036,854,775,808 | 9,223,372,036,854,775,807 |
| int | -2,147,483,648 | 2,147,483,647 |
| smallint | -32,768 | 32,767 |
| tinyint | 0 | 255 |
| bit | 0 | 1 |
| decimal | -10^38 +1 | 10^38 -1 |
| numeric | -10^38 +1 | 10^38 -1 |
| money | -922,337,203,685,477.5808 | +922,337,203,685,477.5807 |
| smallmoney | -214,748.3648 | +214,748.3647 |
Approximate Numeric Data Types
| DATA TYPE | FROM | TO |
|---|---|---|
| float | -1.79E + 308 | 1.79E + 308 |
| real | -3.40E + 38 | 3.40E + 38 |
Date and Time Data Types
| DATA TYPE | FROM | TO |
|---|---|---|
| datetime | Jan 1, 1753 | Dec 31, 9999 |
| smalldatetime | Jan 1, 1900 | Jun 6, 2079 |
| date | Stores a date like June 30, 1991 | |
| time | Stores a time of day like 12:30 P.M. | |
Note − Here, datetime has 3.33 milliseconds accuracy where as smalldatetime has 1 minute accuracy.
Character Strings Data Types
| Sr.No. | DATA TYPE & Description |
|---|---|
| 1 | char Maximum length of 8,000 characters.( Fixed length non-Unicode characters) |
| 2 | varchar Maximum of 8,000 characters.(Variable-length non-Unicode data). |
| 3 | varchar(max) Maximum length of 231characters, Variable-length non-Unicode data (SQL Server 2005 only). |
| 4 | text Variable-length non-Unicode data with a maximum length of 2,147,483,647 characters. |
Unicode Character Strings Data Types
| Sr.No. | DATA TYPE & Description |
|---|---|
| 1 | nchar Maximum length of 4,000 characters.( Fixed length Unicode) |
| 2 | nvarchar Maximum length of 4,000 characters.(Variable length Unicode) |
| 3 | nvarchar(max) Maximum length of 231characters (SQL Server 2005 only).( Variable length Unicode) |
| 4 | ntext Maximum length of 1,073,741,823 characters. ( Variable length Unicode ) |
Binary Data Types
| Sr.No. | DATA TYPE & Description |
|---|---|
| 1 | binary Maximum length of 8,000 bytes(Fixed-length binary data ) |
| 2 | varbinary Maximum length of 8,000 bytes.(Variable length binary data) |
| 3 | varbinary(max) Maximum length of 231 bytes (SQL Server 2005 only). ( Variable length Binary data) |
| 4 | image Maximum length of 2,147,483,647 bytes. ( Variable length Binary Data) |
Misc Data Types
| Sr.No. | DATA TYPE & Description |
|---|---|
| 1 | sql_variant Stores values of various SQL Server-supported data types, except text, ntext, and timestamp. |
| 2 | timestamp Stores a database-wide unique number that gets updated every time a row gets updated |
| 3 | uniqueidentifier Stores a globally unique identifier (GUID) |
| 4 | xml Stores XML data. You can store xml instances in a column or a variable (SQL Server 2005 only). |
| 5 | cursor Reference to a cursor object |
| 6 | table Stores a result set for later processing |
