DATE、DATETIME 和 TIMESTAMP 类型是相关的。本节描述它们的特点，它们的相似之处以及它们的不同之处。MySQL 可以识别多种格式的 DATE、DATETIME 和 TIMESTAMP 值，这些格式在 第 11.1.3 节，“日期和时间字面量” 中有描述。对于 DATE 和 DATETIME 范围描述中，“支持” 意味着虽然早期的值可能有效，但不保证一定可用。The DATE, DATETIME, and TIMESTAMP types are related. This section describes their characteristics, how they are similar, and how they differ. MySQL recognizes DATE, DATETIME, and TIMESTAMP values in several formats, described in Section 11.1.3, “Date and Time Literals”. For the DATE and DATETIME range descriptions, “supported” means that although earlier values might work, there is no guarantee.

DATE 类型用于只包含日期部分而不包含时间部分的值。MySQL 以 'YYYY-MM-DD' 格式检索和显示 DATE 值。支持的范围是 '1000-01-01' 到 '9999-12-31'。The DATE type is used for values with a date part but no time part. MySQL retrieves and displays DATE values in 'YYYY-MM-DD' format. The supported range is '1000-01-01' to '9999-12-31'.

DATETIME 类型用于包含日期和时间部分的值。MySQL 以 DATETIME 格式检索和显示 YYYY-MM-DD hh:mm:ss 值。支持的范围是 '1000-01-01 00:00:00' 到 '9999-12-31 23:59:59'。The DATETIME type is used for values that contain both date and time parts. MySQL retrieves and displays DATETIME values in 'YYYY-MM-DD hh:mm:ss' format. The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59'.

TIMESTAMP 数据类型用于包含日期和时间部分的值。TIMESTAMP 的范围是 '1970-01-01 00:00:01' UTC 到 '2038-01-19 03:14:07' UTC。The TIMESTAMP data type is used for values that contain both date and time parts. TIMESTAMP has a range of '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC.

A DATETIME或者TIMESTAMP value can include a trailing fractional seconds part in up to microseconds (6 digits) precision. In particular, any fractional part in a value inserted into a DATETIME或者TIMESTAMP column is stored rather than discarded. With the fractional part included, the format for these values is 'YYYY-MM-DD hh:mm:ss[.fraction]', the range for DATETIME values is '1000-01-01 00:00:00.000000'到'9999-12-31 23:59:59.499999', and the range for TIMESTAMP values is '1970-01-01 00:00:01.000000'到'2038-01-19 03:14:07.499999'. The fractional part should always be separated from the rest of the time by a decimal point; no other fractional seconds delimiter is recognized. For information about fractional seconds support in MySQL, see Section 13.2.6, “Fractional Seconds in Time Values”.A DATETIME or TIMESTAMP value can include a trailing fractional seconds part in up to microseconds (6 digits) precision. In particular, any fractional part in a value inserted into a DATETIME or TIMESTAMP column is stored rather than discarded. With the fractional part included, the format for these values is 'YYYY-MM-DD hh:mm:ss[.fraction]', the range for DATETIME values is '1000-01-01 00:00:00.000000' to '9999-12-31 23:59:59.499999', and the range for TIMESTAMP values is '1970-01-01 00:00:01.000000' to '2038-01-19 03:14:07.499999'. The fractional part should always be separated from the rest of the time by a decimal point; no other fractional seconds delimiter is recognized. For information about fractional seconds support in MySQL, see Section 13.2.6, “Fractional Seconds in Time Values”.

TIMESTAMP 和 DATETIME 数据类型提供自动初始化和更新为当前日期和时间的功能。更多信息，请参见 第 13.2.5 节，“TIMESTAMP 和 DATETIME 的自动初始化和更新”。The TIMESTAMP and DATETIME data types offer automatic initialization and updating to the current date and time. For more information, see Section 13.2.5, “Automatic Initialization and Updating for TIMESTAMP and DATETIME”.

MySQL 将 TIMESTAMP 值从当前时区转换为 UTC 存储，再从 UTC 转换回当前时区进行检索。（对于其他类型，如 DATETIME，则不会发生此操作。）默认情况下，每个连接的当前时区为服务器时间。时区可以按连接单独设置。只要时区设置保持不变，你检索到的值就与存储的值相同。如果你存储了一个 TIMESTAMP 值，然后更改了时区并检索该值，检索到的值将与存储的值不同。这是因为在两个方向的转换中未使用相同的时区。当前时区可通过 time_zone 系统变量获取。更多信息，请参阅 第 7.1.15 节，“MySQL 服务器时区支持”。MySQL converts TIMESTAMP values from the current time zone to UTC for storage, and back from UTC to the current time zone for retrieval. (This does not occur for other types such as DATETIME.) By default, the current time zone for each connection is the server's time. The time zone can be set on a per-connection basis. As long as the time zone setting remains constant, you get back the same value you store. If you store a TIMESTAMP value, and then change the time zone and retrieve the value, the retrieved value is different from the value you stored. This occurs because the same time zone was not used for conversion in both directions. The current time zone is available as the value of the time_zone system variable. For more information, see Section 7.1.15, “MySQL Server Time Zone Support”.

在向表中插入 TIMESTAMP 或 DATETIME 值时，您可以指定时区偏移。有关更多信息和示例，请参见 第 11.1.3 节，“日期和时间字面值”。You can specify a time zone offset when inserting a TIMESTAMP or DATETIME value into a table. See Section 11.1.3, “Date and Time Literals”, for more information and examples.

如果 SQL 模式允许此转换，无效的 DATE、DATETIME 或 TIMESTAMP 值将被转换为相应类型的“零”值（'0000-00-00' 或 '0000-00-00 00:00:00'）。具体行为取决于是否启用了严格 SQL 模式和 NO_ZERO_DATE SQL 模式；请参阅 第 7.1.11 节，“服务器 SQL 模式”。Invalid DATE, DATETIME, or TIMESTAMP values are converted to the “zero” value of the appropriate type ('0000-00-00' or '0000-00-00 00:00:00'), if the SQL mode permits this conversion. The precise behavior depends on which if any of strict SQL mode and the NO_ZERO_DATE SQL mode are enabled; see Section 7.1.11, “Server SQL Modes”.

您可以在检索 TIMESTAMP 值时使用 CAST() 结合 DATETIME 运算符将其转换为 UTC AT TIME ZONE 值，如下所示：You can convert TIMESTAMP values to UTC DATETIME values when retrieving them using CAST() with the AT TIME ZONE operator, as shown here:

mysql> SELECT col,
     >     CAST(col AT TIME ZONE INTERVAL '+00:00' AS DATETIME) AS ut
     >     FROM ts ORDER BY id;
+---------------------+---------------------+
| col                 | ut                  |
+---------------------+---------------------+
| 2020-01-01 10:10:10 | 2020-01-01 15:10:10 |
| 2019-12-31 23:40:10 | 2020-01-01 04:40:10 |
| 2020-01-01 13:10:10 | 2020-01-01 18:10:10 |
| 2020-01-01 10:10:10 | 2020-01-01 15:10:10 |
| 2020-01-01 04:40:10 | 2020-01-01 09:40:10 |
| 2020-01-01 18:10:10 | 2020-01-01 23:10:10 |
+---------------------+---------------------+

有关语法和更多示例的完整信息，请参阅 CAST() 函数的说明。For complete information regarding syntax and additional examples, see the description of the CAST() function.

注意 MySQL 中日期值解释的某些属性：Be aware of certain properties of date value interpretation in MySQL: