MySQL CAST() 函数

将值转换为 DATE 数据类型：

SELECT CAST("2017-08-29" AS DATE);

定义和用法

CAST() 函数将值（任何类型）转换为指定的数据类型。

提示：另请参阅转变（）功能。

CAST( value AS datatype)

Parameter

Description

value

Required. The value to convert

datatype

Required. The datatype to convert to. Can be one of the following:

Value	Description
DATE	Converts value to DATE. Format: "YYYY-MM-DD"
DATETIME	Converts value to DATETIME. Format: "YYYY-MM-DD HH:MM:SS"
DECIMAL	Converts value to DECIMAL. Use the optional M and D parameters to specify the maximum number of digits (M) and the number of digits following the decimal point (D).
TIME	Converts value to TIME. Format: "HH:MM:SS"
CHAR	Converts value to CHAR (a fixed length string)
NCHAR	Converts value to NCHAR (like CHAR, but produces a string with the national character set)
SIGNED	Converts value to SIGNED (a signed 64-bit integer)
UNSIGNED	Converts value to UNSIGNED (an unsigned 64-bit integer)
BINARY	Converts value to BINARY (a binary string)

工作于：	从 MySQL 4.0 开始