mysql - MySQL WEEK() 的什么模式符合 ISO 8601

Question

MySQL的WEEK()是什么模式函数产生 ISO 8601 week of the year ? WEEK() 的参数 2 根据此图表设置模式:

+--------------------------------------------------------------------+
| Mode | First day of week | Range | Week 1 is the first week ...    |
|------+-------------------+-------+---------------------------------|
| 0    | Sunday            | 0-53  | with a Sunday in this year      |
|------+-------------------+-------+---------------------------------|
| 1    | Monday            | 0-53  | with more than 3 days this year |
|------+-------------------+-------+---------------------------------|
| 2    | Sunday            | 1-53  | with a Sunday in this year      |
|------+-------------------+-------+---------------------------------|
| 3    | Monday            | 1-53  | with more than 3 days this year |
|------+-------------------+-------+---------------------------------|
| 4    | Sunday            | 0-53  | with more than 3 days this year |
|------+-------------------+-------+---------------------------------|
| 5    | Monday            | 0-53  | with a Monday in this year      |
|------+-------------------+-------+---------------------------------|
| 6    | Sunday            | 1-53  | with more than 3 days this year |
|------+-------------------+-------+---------------------------------|
| 7    | Monday            | 1-53  | with a Monday in this year      |
+--------------------------------------------------------------------+

这些模式中的一种是否会提供一年中的 ISO 8601 周？

Answer 1

在 ISO 周编号中，星期一是一周的第一天，因此仅此一项就可以将其缩小为奇数模式之一。

Per Wikipedia :

There are mutually equivalent descriptions of week 01:

• the week with the year's first Thursday in it (the formal ISO definition),
• the week with 4 January in it,
• the first week with the majority (four or more) of its days in the starting year, and
• the week starting with the Monday in the period 29 December – 4 January.

这些描述中的第三个匹配上表中的“今年超过 3 天”，所以现在我们将其缩小到 1 或 3。

最后，仍然来自维基百科(强调添加):

If 1 January is on a Monday, Tuesday, Wednesday or Thursday, it is in week 01. If 1 January is on a Friday, Saturday or Sunday, it is in week 52 or 53 of the previous year (there is no week 00).

因此，范围必须是 1-53，而不是 0-53。这反过来意味着正确的模式是模式 3。