SQL Convert有什么作用？ (What does SQL Convert do? )

It converts from one data type to another data type.

它从一种数据类型转换为另一种数据类型。

句法 (Syntax)

CONVERT (_New Data Type, Expression, Style_)

CONVERT (_New Data Type, Expression, Style_)

• New Data Type:  New data type to be converted too. For example: nvarchar, integer, decimal, date

  新数据类型：也要转换的新数据类型。 例如：nvarchar，整数，十进制，日期

• Expression:  Data to be converted.

  表达式：要转换的数据。

• Style:  Format. For example: The style 110 is USA Date format mm-dd-yyyy

  样式：格式。 例如：样式110为USA日期格式mm-dd-yyyy

示例：将十进制数转换为整数 (Example: Convert a Decimal Number to An Integer)

SELECT CONVERT(INT, 23.456) as IntegerNumber

SELECT CONVERT(INT, 23.456) as IntegerNumber

Note: The result is truncated.

注意：结果被截断。

示例：将字符串转换为日期 (Example: Convert a String to a Date)

SELECT CONVERT(DATE, '20161030') as Date

SELECT CONVERT(DATE, '20161030') as Date

示例：将小数转换为字符串 (Example: Convert a Decimal to a String)

SELECT CONVERT(nvarchar, 20.123) as StringData

SELECT CONVERT(nvarchar, 20.123) as StringData

示例：将整数转换为十进制数 (Example: Convert an Integer Number to a Decimal Number)

SELECT CONVERT(DECIMAL (15,3), 13) as DecimalNumber

SELECT CONVERT(DECIMAL (15,3), 13) as DecimalNumber

示例：将字符串转换为美国日期样式的日期格式 (Example: Convert a String to Date Format in USA Date Style)

SELECT CONVERT(DATE, '20171030' , 110) To_USA_DateFormat

SELECT CONVERT(DATE, '20171030' , 110) To_USA_DateFormat

翻译自: https://www.freecodecamp.org/news/sql-date-format-and-sql-server-convert/