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📜  T-SQL-数据类型

📅  最后修改于: 2020-12-29 04:47:11             🧑  作者: Mango

SQL Server数据类型是一个属性，用于指定任何对象的数据类型。 SQL Server中的每一列，变量和表达式都有相关的数据类型。在创建表时可以使用这些数据类型。您可以根据需要为表列选择特定的数据类型。

SQL Server提供了七个类别，包括要使用的其他数据类型类别。

确切的数字类型

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

数字和十进制是固定精度和小数位数据类型，在功能上等效。

近似数值类型

Type From To
Float -1.79E + 308 1.79E + 308
Real -3.40E + 38 3.40E + 38

日期和时间类型

Type From To

datetime(3.33 milliseconds accuracy)

 Jan 1, 1753 Dec 31, 9999

smalldatetime(1 minute accuracy)

 Jan 1, 1900 Jun 6, 2079

date(1 day accuracy. Introduced in SQL Server 2008)

 Jan 1, 0001 Dec 31, 9999

datetimeoffset(100 nanoseconds accuracy. Introduced in SQL Server 2008)

 Jan 1, 0001 Dec 31, 9999

datetime2(100 nanoseconds accuracy. Introduced in SQL Server 2008)

 Jan 1, 0001 Dec 31, 9999

time(100 nanoseconds accuracy. Introduced in SQL Server 2008)

 00:00:00.0000000 23:59:59.9999999

字符

Sr.No Type & Description
1

char

Fixed-length non-Unicode character data with a maximum length of 8,000 characters.
2

varchar

Variable-length non-Unicode data with a maximum of 8,000 characters.
3

Varchar (max)

Variable-length non-Unicode data with a maximum length of 231 characters (Introduced in SQL Server 2005).
4

text

Variable-length non-Unicode data with a maximum length of 2,147,483,647 characters

的Unicode字符

Sr.No Type & Description
1

nchar

Fixed-length Unicode data with a maximum length of 4,000 characters.
2

nvarchar

Variable-length Unicode data with a maximum length of 4,000 characters.
3

Nvarchar (max)

Variable-length Unicode data with a maximum length of 230 characters (Introduced in SQL Server 2005).
4

ntext

Variable-length Unicode data with a maximum length of 1,073,741,823 characters.

二进制字符串

Sr.No Type & Description
1

binary

Fixed-length binary data with a maximum length of 8,000 bytes.
2

varbinary

Variable-length binary data with a maximum length of 8,000 bytes.
3

varbinary(max)

Variable-length binary data with a maximum length of 231 bytes (Introduced in SQL Server 2005).
4

image

Variable-length binary data with a maximum length of 2,147,483,647 bytes.

其他数据类型

  • sql_variant-存储各种SQL Server支持的数据类型的值，但text，ntext和timestamp除外。

  • 时间戳-存储数据库范围内的唯一编号，该编号在每次更新行时都会更新。

  • uniqueidentifier-存储全局唯一标识符(GUID)。

  • xml-存储XML数据。您可以将XML实例存储在列或变量中(在SQL Server 2005中引入)。

  • cursor-对游标的引用。

  • 表-存储结果集以供以后处理。

  • architectureid-可变长度的系统数据类型，用于表示层次结构中的位置(在SQL Server 2008中引入)。