先看看刪除之前的表結構：

mysql> select * from test;
+------+--------+----------------------------------+------------+------------+------------+------------+
| t_id | t_name | t_password                       | t_birth    | birth      | birth1     | birth2     |
+------+--------+----------------------------------+------------+------------+------------+------------+
|    1 | name1  | 12345678901234567890123456789012 | NULL       | 1990-01-01 | 0000-00-00 | 2013-01-01 |
|    2 | name2  | 12345678901234567890123456789012 | 2013-01-01 | NULL       | 0000-00-00 | 2013-01-01 |
+------+--------+----------------------------------+------------+------------+------------+------------+
2 rows in set (0.00 sec)

執行刪除命令，使用drop關鍵字。
基本的語法為：alter table <表名> drop column <字段名>;

具體的命令如下：

mysql> alter table test drop column birth1;
Query OK, 0 rows affected (0.13 sec)
Records: 0  Duplicates: 0  Warnings: 0

看看刪除后的結果，是不是已經沒有birth1字段了？

mysql> select * from test;
+------+--------+----------------------------------+------------+------------+------------+
| t_id | t_name | t_password                       | t_birth    | birth      | birth2     |
+------+--------+----------------------------------+------------+------------+------------+
|    1 | name1  | 12345678901234567890123456789012 | NULL       | 1990-01-01 | 2013-01-01 |
|    2 | name2  | 12345678901234567890123456789012 | 2013-01-01 | NULL       | 2013-01-01 |
+------+--------+----------------------------------+------------+------------+------------+
2 rows in set (0.00 sec)

關于MySQL中根據生日計算年齡的SQL語句日期函數，本文就介紹這么多，希望對大家有所幫助，謝謝！