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('2031');
+-----------------------+
| dayofweek('2031') |
+-----------------------+
| 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('2005');
+-----------------------+
| dayofweek('2005') |
+-----------------------+
| 7 |
+-----------------------+
1 row in set (0.00 sec)
mysql> select dayofweek('2001');
+-----------------------+
| dayofweek('2001') |
+-----------------------+
| 3 |
+-----------------------+
1 row in set (0.00 sec)
mysql> select dayofweek('2031');
+-----------------------+
| dayofweek('2031') |
+-----------------------+
| 2 |
+-----------------------+
1 row in set (0.00 sec)
mysql> select dayofweek('2030');
+-----------------------+
| dayofweek('2030') |
+-----------------------+
| 1 |
+-----------------------+
1 row in set (0.00 sec)
mysql> select dayofweek('2029');
+-----------------------+
| dayofweek('2029') |
+-----------------------+
| 7 |
+-----------------------+
1 row in set (0.00 sec)
