如何增加数据库条目？

Question

主要问题是假设我有一个值存储在database = 26中,如果用户执行某些操作并且我必须将值增加1,那么在sql中是否有任何预定义的方法来执行此操作.

现在我正在提取值然后添加1然后再次更新条目.

Answer 1

是的,运行如下的SQL:

update yourTableName 
    set theColumnYouWant=theColumnYouWant+1 
    where yourConditions=YourConditionCriteria

更新语法的具体示例:

mysql> select * from first;
+------+-------+
| bob  | title |
+------+-------+
|    1 | aaaa  |
|    2 | bbbb  |
|    3 | cccc  |
|    4 | NULL  |
|    5 | eeee  |
+------+-------+
5 rows in set (0.00 sec)

mysql> update first set bob=bob+1 where title='eeee';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from first;
+------+-------+
| bob  | title |
+------+-------+
|    1 | aaaa  |
|    2 | bbbb  |
|    3 | cccc  |
|    4 | NULL  |
|    6 | eeee  |
+------+-------+
5 rows in set (0.00 sec)