SQL DELETE 语句
SQL DELETE 语句
DELETE语句用于删除表中的现有记录。
删除语法
DELETE FROM table_name WHERE condition;
注意:删除表中的记录时要小心!请注意DELETE语句中的WHERE子句.WHERE子句指定应删除哪些记录。如果省略WHERE子句,表中的所有记录都将被删除!
演示数据库
以下是Northwind示例数据库中“Customers”表的选择:
CustomerID |
CustomerName |
ContactName |
Address |
City |
PostalCode |
Country |
1 |
Alfreds Futterkiste |
Maria Anders |
Obere Str. 57 |
Berlin |
12209 |
Germany |
2 |
Ana Trujillo Emparedados y helados |
Ana Trujillo |
Avda. de la Constituciуn 2222 |
Mйxico D.F. |
05021 |
Mexico |
3 |
Antonio Moreno Taquerнa |
Antonio Moreno |
Mataderos 2312 |
Mйxico D.F. |
05023 |
Mexico |
4 |
Around the Horn |
Thomas Hardy |
120 Hanover Sq. |
London |
WA1 1DP |
UK |
5 |
Berglunds snabbkцp |
Christina Berglund |
Berguvsvдgen 8 |
Luleе |
S-958 22 |
Sweden |
SQL DELETE 实例
以下SQL语句从“Customers”表中删除客户“Alfreds Futterkiste”:
实例
DELETE FROM CustomersWHERE CustomerName='Alfreds Futterkiste';
运行实例»
“Customers”表结果如下:
CustomerID |
CustomerName |
ContactName |
Address |
City |
PostalCode |
Country |
2 |
Ana Trujillo Emparedados y helados |
Ana Trujillo |
Avda. de la Constituciуn 2222 |
Mйxico D.F. |
05021 |
Mexico |
3 |
Antonio Moreno Taquerнa |
Antonio Moreno |
Mataderos 2312 |
Mйxico D.F. |
05023 |
Mexico |
4 |
Around the Horn |
Thomas Hardy |
120 Hanover Sq. |
London |
WA1 1DP |
UK |
5 |
Berglunds snabbkцp |
Christina Berglund |
Berguvsvдgen 8 |
Luleе |
S-958 22 |
Sweden |
删除所有记录
可以删除表中的所有行而不删除表。这意味着表结构,属性和索引将保持不变:
以下SQL语句删除“Customers”表中的所有行,而不删除表:
实例
DELETE FROM Customers;
运行实例»