摘要:

下文讲述MySQL数据库中获取一个日期对应星期数的方法分享，如下所示；

实现思路:

使用MySQL中日期函数dayofweek即可获取指定日期所对应的星期数

dayOfWeek返回值说明:

星期天:返回1

星期一:返回2

星期二:返回3

星期三:返回4

星期四:返回5

星期五:返回5

星期六:返回7

dayOfWeek函数注意事项:

输入的参数值必须可以转换为日期，否则会返回NULL

dayofWeek函数示例说明:

mysql> select dayofweek('23');

+-----------------+

| dayofweek('23') |

+-----------------+

| NULL |

+-----------------+

1 row in set, 1 warning (0.00 sec)

mysql> select dayofweek('20200931');

+-----------------------+

| dayofweek('20200931') |

+-----------------------+

| NULL |

+-----------------------+

1 row in set, 1 warning (0.00 sec)

mysql> select dayofweek('abdcd');

+--------------------+

| dayofweek('abdcd') |

+--------------------+

| NULL |

+--------------------+

1 row in set, 1 warning (0.00 sec)

mysql> select dayofweek('20200905');

+-----------------------+

| dayofweek('20200905') |

+-----------------------+

| 7 |

+-----------------------+

1 row in set (0.00 sec)

mysql> select dayofweek('20200901');

+-----------------------+

| dayofweek('20200901') |

+-----------------------+

| 3 |

+-----------------------+

1 row in set (0.00 sec)

mysql> select dayofweek('20200831');

+-----------------------+

| dayofweek('20200831') |

+-----------------------+

| 2 |

+-----------------------+

1 row in set (0.00 sec)

mysql> select dayofweek('20200830');

+-----------------------+

| dayofweek('20200830') |

+-----------------------+

| 1 |

+-----------------------+

1 row in set (0.00 sec)

mysql> select dayofweek('20200829');

+-----------------------+

| dayofweek('20200829') |

+-----------------------+

| 7 |

+-----------------------+

1 row in set (0.00 sec)