Field | Type | Null | Key | Default | Extra |
+-----------------+------------------+------+-----+-------------------+-----------------------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| name | varchar(100) | NO | | NULL | |
| organization_id | int(10) unsigned | NO | MUL | NULL | |
| arena_id | int(10) unsigned | NO | MUL | NULL | |
| trainer_id | int(10) unsigned | YES | MUL | NULL | |
| type | varchar(1) | NO | | NULL | |
| sports | int(11) | NO | | NULL | |
| gender | varchar(1) | YES | | NULL | |
| max_entries | int(11) | YES | | NULL | |
| from_date | date | NO | | NULL | |
| to_date | date | YES | | NULL | |
| from_time | time | YES | | NULL | |
| to_time | time | YES | | NULL | |
| day_slot | int(11) | YES | | NULL | |
| fees | double | NO | | NULL | |
| bill_cycle | tinyint(4) | NO | | 0 | |
| due_after | tinyint(4) | YES | | 0 | |
| created_at | datetime | NO | | CURRENT_TIMESTAMP | |
| updated_at | datetime | YES | | NULL | on update CURRENT_TIMESTAMP |
| deleted_at | datetime | YES | | NULL |
coaching_class_entries表
| Field | Type | Null | Key | Default | Extra |
+-------------------+------------------+------+-----+-------------------+-----------------------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| user_id | int(10) unsigned | NO | MUL | NULL | |
| coaching_class_id | int(10) unsigned | NO | MUL | NULL | |
| fees | double | NO | | NULL | |
| bill_cycle | int(4) | NO | | 0 | |
| from_date | date | NO | | NULL | |
| to_date | date | YES | | NULL | |
| tax_group_id | int(10) unsigned | YES | MUL | NULL | |
| last_bill_date | date | YES | | NULL | |
| next_bill_date | date | YES | | NULL | |
| comments | varchar(100) | YES | | NULL | |
| created_at | datetime | NO | | CURRENT_TIMESTAMP | |
| updated_at | datetime | YES | | NULL | on update CURRENT_TIMESTAMP |
| deleted_at | datetime | YES | | NULL | |
+-------------------+------------------+------+-----+-------------------+-----
我在bill_cycle表中添加了一个新列Coaching_class_entries，并且在另一个名为bill_cycle的表中有相同的列Coaching_classes。现在，我想将bill_cycle的值从Coaching_classes复制到Coaching_class_entries bill_cycle列，以便coaching_class_entries的所有行。我是新手数据库，任何人都可以给我一些提示。
答案 0 :(得分：2)
我认为一个简单的更新连接应该在这里工作：
UPDATE Coaching_class_entries t1
INNER JOIN Coaching_classes t2
ON t1.coaching_class_id = t2.id
SET t1.bill_cycle = t2.bill_cycle;