string sql = "UPDATE parking SET card_value = '', car_number='',car_user='',state=0 WHERE parking_id ="+parkid;
时间: 2023-05-15 14:06:38 浏览: 51
这是一段用于更新停车场信息的 SQL 语句,其中包括将卡片值、车牌号、车主信息清空,同时将停车状态设置为 0。其中 parkid 是一个变量,需要在代码中赋值。如果你需要更详细的代码实现,可以参考相关的编程教程或者文档。
相关问题
String sql = "update actor set actor_name=? where id=?";
This is a SQL statement that updates the name of an actor in a database table called "actor". The statement uses two placeholders indicated by the question marks:
1. The first placeholder is for the new name of the actor and will be replaced with a value when the statement is executed.
2. The second placeholder is for the ID of the actor whose name will be updated and will also be replaced with a value when the statement is executed.
The statement is dynamic because it can be used to update any actor's name by passing in the appropriate values for the placeholders.
String sql = "UPDATE edit SET new_text = ? WHERE edit_name=111";
这是一个更新 SQL 语句,将 edit 表中 edit_name 为 111 的记录的 new_text 字段更新为指定的值。其中的问号是占位符,需要使用 PreparedStatement 对象来执行该 SQL 语句,并将实际的值传入问号对应的位置。具体的代码可能如下:
```
String sql = "UPDATE edit SET new_text = ? WHERE edit_name=111";
try (Connection conn = DriverManager.getConnection(url, user, password);
PreparedStatement pstmt = conn.prepareStatement(sql)) {
pstmt.setString(1, "new value"); // 将问号替换为指定的值
int rows = pstmt.executeUpdate(); // 执行更新操作
System.out.println(rows + " rows updated."); // 输出更新的行数
} catch (SQLException e) {
e.printStackTrace();
}
```