yearweek

返回给定日期对应的年份和周数。该函数和 MySQL yearweek() 函数原理相同。

该函数从 3.3 版本开始支持。

语法

INT YEARWEEK(DATETIME|DATE date[, INT mode])

参数说明

• date: 支持的数据类型为 DATETIME 或 DATE。

• mode: 可选，支持的数据类型为 INT。用于确定周数计算逻辑，即一周起始于周日还是周一，以及返回值的范围是 0 到 53 还是 1 到 53。该参数取值范围 0~7，默认值为 0。如果未指定该参数，默认按照模式 0 对应的规则计算。具体的语义如下：

  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 4 or more days this year
  2       Sunday               1-53     with a Sunday in this year
  3       Monday               1-53     with 4 or more days this year
  4       Sunday               0-53     with 4 or more days this year
  5       Monday               0-53     with a Monday in this year
  6       Sunday               1-53     with 4 or more days this year
  7       Monday               1-53     with a Monday in this year

返回值说明

返回 INT 类型的值。取值范围 0~53，具体的范围由 mode 参数决定。 如果 date 取值类型不合法或输入为空，则返回 NULL。

示例

mysql> SELECT YEARWEEK('2007-01-01', 0);
+---------------------------+
| yearweek('2007-01-01', 0) |
+---------------------------+
|                    200653 |
+---------------------------+

mysql> SELECT YEARWEEK('2007-01-01', 1);
+---------------------------+
| yearweek('2007-01-01', 1) |
+---------------------------+
|                    200701 |
+---------------------------+

mysql> SELECT YEARWEEK('2007-01-01', 2);
+---------------------------+
| yearweek('2007-01-01', 2) |
+---------------------------+
|                    200653 |
+---------------------------+
1 row in set (0.01 sec)